.site-ui {
  --bg: #E6EAE3;
  --text: #37423B;
  --muted: #5F6C62;
  --accent: #276846;
  --accent-light: #3B8A5E;
  --accent-teal: #3FA08C;
  --accent-rgb: 39, 104, 70;
  --bloom-green: #A0CDA2;
  --bloom-green-rgb: 160, 205, 162;
  --bloom-pink: #F6A6B3;
  --bloom-mauve: #DEB7D5;
  --bloom-cream: #FFFAC8;
  --bloom-sky: #A9D4E5;
  --ink-on-bloom: #1E3B29;
  --error: #B0485E;
  --lcd-glass: #CDD3C2;
  --lcd-ink: #46523F;
  --shadow-light: rgba(255, 255, 255, 0.6);
  --shadow-dark: rgba(146, 163, 143, 0.55);
  --shadow-dark-heavy: rgba(146, 163, 143, 0.7);
  --btn-accent-shadow-light: rgba(39, 104, 70, 0.3);
  --btn-accent-shadow-dark: rgba(39, 104, 70, 0.45);
  --overlay: rgba(24, 32, 26, 0.5);
  --transparent: rgba(255, 255, 255, 0);
  --surface-raised: var(--bg);
  --surface-hover: var(--bg);
  --surface-pressed: var(--bg);
  --surface-strong: var(--bg);
  --surface-border: transparent;
  --surface-border-soft: transparent;
  --surface-highlight: transparent;
  --surface-blur: none;
  --surface: var(--surface-raised);
  --line: var(--surface-border-soft);
  --glass-bg: var(--bg);
  --glass-surface: var(--surface-raised);
  --glass-surface-strong: var(--surface-strong);
  --glass-surface-solid: var(--bg);
  --glass-line: var(--surface-border-soft);
  --glass-text: var(--text);
  --glass-muted: var(--muted);
  --glass-primary: var(--accent);
  --glass-primary-hover: var(--accent-light);
  --glass-secondary: var(--accent-teal);
  --glass-link: var(--accent);
  --surface-shadow: 9px 9px 16px var(--shadow-dark), -9px -9px 16px var(--shadow-light);
  --surface-shadow-hover: 13px 13px 22px var(--shadow-dark-heavy), -13px -13px 22px var(--shadow-light);
  --surface-shadow-small: 5px 5px 10px var(--shadow-dark), -5px -5px 10px var(--shadow-light);
  --surface-shadow-pressed: inset 6px 6px 10px var(--shadow-dark), inset -6px -6px 10px var(--shadow-light);
  --surface-shadow-deep: inset 10px 10px 20px var(--shadow-dark-heavy), inset -10px -10px 20px var(--shadow-light);
  --surface-shadow-inset-small: inset 3px 3px 6px var(--shadow-dark), inset -3px -3px 6px var(--shadow-light);
  --dialog-shadow: 18px 18px 36px var(--shadow-dark-heavy), -18px -18px 36px var(--shadow-light);
  --primary-text: rgba(255, 255, 255, 1);
  --placeholder: #7A877C;
  --select-option-bg: #E6EAE3;
  --pet-eye-glow: rgba(59, 138, 94, 0.42);
  --bloom-green-soft: rgba(160, 205, 162, 0.36);
  --bloom-pink-soft: rgba(246, 166, 179, 0.32);
  --bloom-mauve-soft: rgba(222, 183, 213, 0.32);
  --bloom-cream-soft: rgba(255, 250, 200, 0.55);
  --bloom-sky-soft: rgba(169, 212, 229, 0.4);
  --glow-green: rgba(160, 205, 162, 0.35);
  --glow-pink: rgba(246, 166, 179, 0.32);
  --glow-mauve: rgba(222, 183, 213, 0.3);
  --glow-sky: rgba(169, 212, 229, 0.32);
  --glow-cream: rgba(255, 250, 200, 0.26);
  --focus-inner: var(--bg);
  --status-good: var(--accent-teal);
  --status-bad: var(--error);
  --transition-ui: 300ms ease-out;
  --page-bg: var(--bg);
  --card-bg: var(--surface-raised);
  --border: var(--surface-border-soft);
  --primary: var(--accent);
  --primary-hover: var(--accent-light);
  --secondary: var(--muted);
  --danger: var(--error);
  --floating-shadow: 0 10px 0 rgba(126, 143, 124, 0.32), 18px 22px 38px var(--shadow-dark-heavy), -10px -10px 24px var(--shadow-light);
}

.site-ui [hidden] {
  display: none !important;
}

[data-theme="dark"] .site-ui {
  --bg: #14171C;
  --text: #E8ECEF;
  --muted: #9AA4AD;
  --accent: #A0CDA2;
  --accent-light: #C4E4C6;
  --accent-teal: #4EC9B0;
  --accent-rgb: 160, 205, 162;
  --ink-on-bloom: #0F1F15;
  --error: #F6A6B3;
  --lcd-glass: rgba(8, 12, 10, 0.55);
  --lcd-ink: #A0CDA2;
  --glass-fill: rgba(255, 255, 255, 0.07);
  --glass-fill-hover: rgba(255, 255, 255, 0.11);
  --glass-fill-strong: rgba(255, 255, 255, 0.13);
  --glass-fill-pressed: rgba(255, 255, 255, 0.05);
  --glass-border: rgba(255, 255, 255, 0.14);
  --glass-border-soft: rgba(255, 255, 255, 0.08);
  --glass-highlight: rgba(255, 255, 255, 0.22);
  --glass-well: rgba(0, 0, 0, 0.3);
  --glass-shadow-color: rgba(0, 0, 0, 0.45);
  --glass-shadow-hover: rgba(0, 0, 0, 0.5);
  --overlay: rgba(0, 0, 0, 0.55);
  --surface-raised: var(--glass-fill);
  --surface-hover: var(--glass-fill-hover);
  --surface-pressed: var(--glass-fill-pressed);
  --surface-strong: var(--glass-fill-strong);
  --surface-border: var(--glass-border);
  --surface-border-soft: var(--glass-border-soft);
  --surface-highlight: var(--glass-highlight);
  --surface-blur: blur(20px) saturate(160%);
  --surface-shadow: inset 0 1px 0 var(--glass-highlight), 0 18px 40px var(--glass-shadow-color);
  --surface-shadow-hover: inset 0 1px 0 var(--glass-highlight), 0 24px 48px var(--glass-shadow-hover);
  --surface-shadow-small: inset 0 1px 0 var(--glass-highlight), 0 10px 24px var(--glass-shadow-color);
  --surface-shadow-pressed: inset 0 2px 8px var(--glass-shadow-color);
  --surface-shadow-deep: inset 0 2px 10px var(--glass-shadow-color), inset 0 -1px 0 var(--glass-border-soft);
  --surface-shadow-inset-small: inset 0 2px 10px var(--glass-shadow-color), inset 0 -1px 0 var(--glass-border-soft);
  --dialog-shadow: inset 0 1px 0 var(--glass-highlight), 0 24px 60px var(--glass-shadow-color);
  --primary-text: var(--ink-on-bloom);
  --placeholder: #6B7681;
  --select-option-bg: #24292F;
  --pet-eye-glow: var(--glow-green);
  --focus-inner: var(--bg);
  --status-good: var(--accent-teal);
  --status-bad: var(--error);
  --page-bg: var(--bg);
  --card-bg: var(--surface-raised);
  --border: var(--surface-border-soft);
  --primary: var(--accent);
  --primary-hover: var(--accent-light);
  --secondary: var(--muted);
  --danger: var(--error);
  --floating-shadow: inset 0 1px 0 var(--glass-highlight), 0 10px 0 rgba(0, 0, 0, 0.18), 0 28px 64px rgba(0, 0, 0, 0.56);
}

.student-ui.site-ui {
  min-height: 100vh;
  overflow-x: clip;
  background: var(--bg);
  color: var(--text);
  font-family: "DM Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  letter-spacing: 0;
  transition:
    background var(--transition-ui),
    color var(--transition-ui),
    border-color var(--transition-ui),
    box-shadow var(--transition-ui);
}

[data-theme="dark"] .student-ui.site-ui {
  background:
    radial-gradient(640px 420px at 12% 8%, var(--glow-green), var(--transparent) 60%),
    radial-gradient(520px 520px at 88% 18%, var(--glow-mauve), var(--transparent) 60%),
    radial-gradient(720px 520px at 70% 95%, var(--glow-sky), var(--transparent) 60%),
    radial-gradient(480px 380px at 30% 80%, var(--glow-pink), var(--transparent) 60%),
    var(--bg);
  background-attachment: fixed;
}

.site-ui *,
.site-ui *::before,
.site-ui *::after {
  box-sizing: border-box;
  letter-spacing: 0;
}

.site-ui button,
.site-ui a,
.site-ui input,
.site-ui select,
.site-ui dialog,
.site-ui .site-pet__head,
.site-ui .site-pet__body,
.site-ui .site-pet__bubble {
  transition:
    background var(--transition-ui),
    color var(--transition-ui),
    border-color var(--transition-ui),
    box-shadow var(--transition-ui),
    transform var(--transition-ui),
    opacity var(--transition-ui),
    backdrop-filter var(--transition-ui);
}

.site-ui .home-topbar {
  position: sticky;
  top: 0;
  z-index: 30;
  border: 1px solid transparent;
  border-width: 0 0 1px;
  padding-top: env(safe-area-inset-top);
  background: var(--bg);
  box-shadow: 9px 9px 16px var(--shadow-dark), -9px -9px 16px var(--shadow-light);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

[data-theme="dark"] .site-ui .home-topbar {
  border-color: var(--surface-border);
  background: var(--surface-strong);
  box-shadow: inset 0 1px 0 var(--surface-highlight), 0 18px 40px var(--glass-shadow-color);
  -webkit-backdrop-filter: var(--surface-blur);
  backdrop-filter: var(--surface-blur);
}

.site-ui .home-topbar__inner,
.site-ui .home-main {
  width: min(1280px, calc(100% - 48px));
  margin-inline: auto;
}

.site-ui .home-topbar__inner {
  min-height: 76px;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 24px;
}

.site-ui .home-brand {
  min-width: 0;
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--text);
  font-family: "Plus Jakarta Sans", "DM Sans", sans-serif;
  font-size: 1.15rem;
  font-weight: 800;
  text-decoration: none;
}

.site-ui .home-brand__mark {
  width: 42px;
  height: 42px;
  flex: 0 0 42px;
  display: grid;
  place-items: center;
  border: 1px solid transparent;
  border-radius: 16px;
  background: var(--accent);
  color: var(--primary-text);
  box-shadow: 5px 5px 10px var(--btn-accent-shadow-dark), -5px -5px 10px var(--btn-accent-shadow-light);
  font-family: "Plus Jakarta Sans", sans-serif;
  font-size: 1.1rem;
  font-weight: 800;
}

[data-theme="dark"] .site-ui .home-brand__mark {
  border-color: var(--surface-border);
  box-shadow: 0 8px 24px var(--glow-green);
}

.site-ui .home-nav-actions {
  min-width: 0;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 4px;
}

.site-ui .home-nav-button,
.site-ui .home-header-control {
  min-height: 44px;
  border: 1px solid transparent;
  border-radius: 16px;
  background: transparent;
  box-shadow: none;
  color: var(--muted);
}

.site-ui .home-nav-button {
  padding: 10px 14px;
  font: 700 0.9rem/1.2 "DM Sans", sans-serif;
}

.site-ui .home-nav-button:hover,
.site-ui .home-nav-button:focus-visible,
.site-ui .home-header-control:hover,
.site-ui .home-header-control:focus-visible {
  border-color: transparent;
  background: var(--bg);
  box-shadow: var(--surface-shadow-small);
  color: var(--text);
  transform: translateY(-1px);
}

[data-theme="dark"] .site-ui .home-nav-button:hover,
[data-theme="dark"] .site-ui .home-nav-button:focus-visible,
[data-theme="dark"] .site-ui .home-header-control:hover,
[data-theme="dark"] .site-ui .home-header-control:focus-visible {
  border-color: var(--surface-border);
  background: var(--surface-raised);
}

.site-ui .home-nav-button:active,
.site-ui .home-header-control:active,
.site-ui .home-header-control.is-open {
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-pressed);
  transform: translateY(0.5px);
}

.site-ui .home-nav-button--logout {
  color: var(--error);
}

.site-ui .home-nav-button--logout:hover,
.site-ui .home-nav-button--logout:focus-visible {
  color: var(--error);
}

.site-ui .home-header-controls {
  display: flex;
  align-items: center;
  gap: 4px;
}

.site-ui .home-header-control {
  position: relative;
  width: 44px;
  height: 44px;
  flex: 0 0 44px;
  display: grid;
  place-items: center;
  padding: 0;
}

.site-ui .home-theme-icon {
  position: absolute;
  width: 22px;
  height: 22px;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
  transition:
    transform 0.4s cubic-bezier(0.45, 0, 0.25, 1),
    opacity 0.3s ease-out;
}

.site-ui .home-theme-icon--sun {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

.site-ui .home-theme-icon--moon {
  opacity: 0;
  transform: rotate(-90deg) scale(0.6);
}

[data-theme="dark"] .site-ui .home-theme-icon--sun {
  opacity: 0;
  transform: rotate(90deg) scale(0.6);
}

[data-theme="dark"] .site-ui .home-theme-icon--moon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

.site-ui .home-menu-toggle {
  display: none;
}

.site-ui .home-menu-toggle span {
  position: absolute;
  width: 20px;
  height: 2px;
  border-radius: 999px;
  background: currentColor;
  transition: transform var(--transition-ui), opacity var(--transition-ui);
}

.site-ui .home-menu-toggle span:first-child {
  transform: translateY(-6px);
}

.site-ui .home-menu-toggle span:last-child {
  transform: translateY(6px);
}

.site-ui .home-menu-toggle.is-open span:first-child {
  transform: rotate(45deg);
}

.site-ui .home-menu-toggle.is-open span:nth-child(2) {
  opacity: 0;
}

.site-ui .home-menu-toggle.is-open span:last-child {
  transform: rotate(-45deg);
}

.site-ui .home-main {
  min-height: calc(100vh - 76px);
  padding: 72px 0 calc(88px + env(safe-area-inset-bottom));
}

.site-ui .home-section-heading {
  margin-bottom: 48px;
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 32px;
}

.site-ui .home-section-heading h1,
.site-ui .profile-dialog__header h2,
.site-ui .profile-pet-settings h3 {
  margin: 0;
  color: var(--text);
  font-family: "Plus Jakarta Sans", "DM Sans", sans-serif;
}

.site-ui .home-section-heading h1 {
  font-size: 3rem;
  font-weight: 800;
  line-height: 1.08;
}

.site-ui .home-eyebrow {
  margin: 0 0 10px;
  color: var(--accent);
  font-size: 0.72rem;
  font-weight: 700;
  line-height: 1.3;
  text-transform: uppercase;
}

.site-ui .home-heading-actions {
  display: flex;
  flex: 0 0 auto;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 16px;
}

.site-ui .btn-primary,
.site-ui .btn-secondary,
.site-ui .pdf-download-action {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid transparent;
  border-radius: 16px;
  padding: 12px 18px;
  font: 700 0.9rem/1.2 "DM Sans", sans-serif;
  text-align: center;
  text-decoration: none;
}

.site-ui .btn-primary,
.site-ui .pdf-download-action {
  background: var(--accent);
  box-shadow: 7px 7px 14px var(--btn-accent-shadow-dark), -7px -7px 14px var(--btn-accent-shadow-light);
  color: var(--primary-text);
}

[data-theme="dark"] .site-ui .btn-primary,
[data-theme="dark"] .site-ui .pdf-download-action {
  border-color: var(--surface-border);
  box-shadow: 0 8px 24px var(--glow-green);
}

.site-ui .btn-secondary,
.site-ui .pdf-download-action--answer {
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow);
  color: var(--text);
}

[data-theme="dark"] .site-ui .btn-secondary,
[data-theme="dark"] .site-ui .pdf-download-action--answer {
  border-color: var(--surface-border);
}

.site-ui .btn-primary:hover,
.site-ui .btn-secondary:hover,
.site-ui .pdf-download-action:hover {
  background: var(--accent-light);
  box-shadow: var(--surface-shadow-hover);
  color: var(--primary-text);
  transform: translateY(-1px);
}

.site-ui .btn-secondary:hover,
.site-ui .pdf-download-action--answer:hover {
  background: var(--surface-hover);
  color: var(--text);
}

.site-ui .btn-primary:active,
.site-ui .btn-secondary:active,
.site-ui .pdf-download-action:active {
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-pressed);
  color: var(--text);
  transform: translateY(0.5px);
}

.site-ui button:disabled,
.site-ui .is-disabled {
  cursor: not-allowed;
  box-shadow: none;
  opacity: 0.45;
  transform: none;
}

.site-ui .course-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 32px;
}

.site-ui .course-card {
  --subject-bloom: var(--bloom-green);
  --subject-soft: var(--bloom-green-soft);
  --subject-glow: var(--glow-green);
  width: 100%;
  min-width: 0;
  min-height: 438px;
  display: flex;
  flex-direction: column;
  align-items: center;
  border: 1px solid transparent;
  border-radius: 32px;
  padding: 28px 24px 24px;
  overflow: hidden;
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow);
  color: var(--text);
  text-align: left;
  isolation: isolate;
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

.site-ui .course-card--chemistry {
  --subject-bloom: var(--bloom-sky);
  --subject-soft: var(--bloom-sky-soft);
  --subject-glow: var(--glow-sky);
}

.site-ui .course-card--sciences {
  --subject-bloom: var(--bloom-cream);
  --subject-soft: var(--bloom-cream-soft);
  --subject-glow: var(--glow-cream);
}

.site-ui .course-card--economics {
  --subject-bloom: var(--bloom-pink);
  --subject-soft: var(--bloom-pink-soft);
  --subject-glow: var(--glow-pink);
}

.site-ui .course-card--default {
  --subject-bloom: var(--bloom-mauve);
  --subject-soft: var(--bloom-mauve-soft);
  --subject-glow: var(--glow-mauve);
}

[data-theme="dark"] .site-ui .course-card {
  border-color: var(--surface-border);
  -webkit-backdrop-filter: var(--surface-blur);
  backdrop-filter: var(--surface-blur);
}

[data-theme="dark"] .site-ui .course-card::before {
  content: "";
  position: absolute;
  inset: 18%;
  z-index: -1;
  border-radius: 50%;
  background: var(--subject-glow);
  filter: blur(48px);
  pointer-events: none;
}

.site-ui .course-card:not(:disabled):hover,
.site-ui .course-card:focus-visible {
  border-color: transparent;
  background: var(--surface-hover);
  box-shadow: var(--surface-shadow-hover);
  transform: translateY(-3px);
}

[data-theme="dark"] .site-ui .course-card:not(:disabled):hover,
[data-theme="dark"] .site-ui .course-card:focus-visible {
  border-color: var(--surface-border);
}

.site-ui .course-card:not(:disabled):active {
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-pressed);
  transform: translateY(0.5px);
}

.site-ui .subject-book {
  position: relative;
  width: 188px;
  height: 244px;
  flex: 0 0 244px;
  margin: 0 auto 20px;
}

.site-ui .subject-book__pages {
  position: absolute;
  top: 8px;
  right: 0;
  width: 178px;
  height: 230px;
  border: 1px solid transparent;
  border-radius: 16px;
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
}

[data-theme="dark"] .site-ui .subject-book__pages {
  border-color: var(--surface-border-soft);
  background: var(--glass-well);
}

.site-ui .subject-book__cover {
  position: absolute;
  inset: 0 auto auto 0;
  width: 178px;
  height: 230px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  border: 1px solid transparent;
  border-radius: 24px;
  padding: 22px 18px 18px 38px;
  overflow: hidden;
  background: var(--bg);
  box-shadow: var(--surface-shadow-small);
  color: var(--text);
}

[data-theme="dark"] .site-ui .subject-book__cover {
  border-color: var(--surface-border);
  background: var(--surface-strong);
  box-shadow: inset 0 1px 0 var(--surface-highlight), 0 12px 28px var(--glass-shadow-color);
  -webkit-backdrop-filter: var(--surface-blur);
  backdrop-filter: var(--surface-blur);
}

.site-ui .subject-book__cover::before {
  content: "";
  position: absolute;
  top: 18px;
  right: 18px;
  bottom: auto;
  width: 8px;
  height: 8px;
  border: 0;
  border-radius: 50%;
  background: var(--subject-bloom);
  box-shadow: 0 0 8px var(--subject-glow);
  transform: none;
}

.site-ui .subject-book__spine {
  position: absolute;
  inset: 0 auto 0 0;
  width: 24px;
  border: 0;
  border-radius: 24px 0 0 24px;
  background: var(--subject-soft);
  box-shadow: var(--surface-shadow-inset-small);
}

.site-ui .subject-book__level {
  color: var(--muted);
  font-size: 0.68rem;
  font-weight: 700;
  opacity: 1;
}

.site-ui .subject-book__emblem {
  min-width: 58px;
  min-height: 58px;
  margin-top: 26px;
  display: grid;
  place-items: center;
  border: 0;
  border-radius: 18px;
  padding: 8px;
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
  color: var(--text);
  font-family: "Plus Jakarta Sans", "DM Sans", sans-serif;
  font-size: 1.05rem;
  font-weight: 800;
  line-height: 1;
}

[data-theme="dark"] .site-ui .subject-book__emblem {
  border: 1px solid var(--surface-border-soft);
  background: var(--glass-well);
  color: var(--subject-bloom);
  text-shadow: 0 0 12px var(--subject-glow);
}

.site-ui .subject-book__name {
  width: 100%;
  margin-top: 14px;
  overflow-wrap: anywhere;
  color: var(--text);
  font-family: "Plus Jakarta Sans", "DM Sans", sans-serif;
  font-size: 0.96rem;
  font-weight: 700;
  line-height: 1.2;
}

.site-ui .subject-book__code {
  max-width: 100%;
  margin-top: auto;
  border-radius: 12px;
  padding: 5px 8px;
  overflow-wrap: anywhere;
  background: var(--lcd-glass);
  box-shadow: var(--surface-shadow-inset-small);
  color: var(--lcd-ink);
  font-family: "Share Tech Mono", ui-monospace, monospace;
  font-size: 0.68rem;
  font-weight: 400;
  line-height: 1.1;
}

[data-theme="dark"] .site-ui .subject-book__code {
  border: 1px solid var(--surface-border-soft);
  text-shadow: 0 0 8px var(--glow-green);
}

.site-ui .course-card__details {
  width: 100%;
  min-width: 0;
  display: flex;
  flex: 1;
  flex-direction: column;
}

.site-ui .course-card__title {
  overflow-wrap: anywhere;
  color: var(--text);
  font-family: "Plus Jakarta Sans", "DM Sans", sans-serif;
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.3;
}

.site-ui .course-card__qualification,
.site-ui .course-card__stats {
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 500;
  line-height: 1.45;
}

.site-ui .course-card__qualification {
  margin-top: 6px;
}

.site-ui .course-card__stats {
  margin-top: 10px;
}

.site-ui .course-card__action {
  margin-top: auto;
  padding-top: 14px;
  color: var(--accent);
  font-size: 0.84rem;
  font-weight: 700;
}

.site-ui .course-card__action::after {
  content: " \2192";
}

.site-ui .course-card--loading {
  min-height: 438px;
  cursor: default;
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
}

[data-theme="dark"] .site-ui .course-card--loading {
  border-color: var(--surface-border-soft);
  background: var(--glass-well);
}

.site-ui .course-grid__empty {
  grid-column: 1 / -1;
  margin: 0;
  border: 1px solid transparent;
  border-radius: 32px;
  padding: 40px;
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow);
  color: var(--muted);
  text-align: center;
}

[data-theme="dark"] .site-ui .course-grid__empty {
  border-color: var(--surface-border);
  -webkit-backdrop-filter: var(--surface-blur);
  backdrop-filter: var(--surface-blur);
}

.site-ui .home-status,
.site-ui .pdf-download-status,
.site-ui .tip {
  color: var(--muted);
}

.site-ui .home-status {
  min-height: 1.35rem;
  margin: 22px 0 0;
  font-size: 0.82rem;
}

.site-ui .good {
  color: var(--status-good);
}

.site-ui .bad {
  color: var(--status-bad);
}

.site-ui .profile-dialog {
  width: min(720px, calc(100% - 32px));
  max-height: min(780px, calc(100vh - 32px));
  border: 1px solid transparent;
  border-radius: 32px;
  padding: 0;
  overflow: auto;
  background: var(--bg);
  box-shadow: var(--dialog-shadow);
  color: var(--text);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

[data-theme="dark"] .site-ui .profile-dialog {
  border-color: var(--surface-border);
  background: var(--surface-strong);
  -webkit-backdrop-filter: var(--surface-blur);
  backdrop-filter: var(--surface-blur);
}

.site-ui .profile-dialog::backdrop {
  background: var(--overlay);
  -webkit-backdrop-filter: blur(2px);
  backdrop-filter: blur(2px);
}

[data-theme="dark"] .site-ui .profile-dialog::backdrop {
  -webkit-backdrop-filter: blur(4px);
  backdrop-filter: blur(4px);
}

.site-ui .profile-dialog__shell {
  padding: 28px;
}

.site-ui .profile-dialog__header {
  margin-bottom: 22px;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
}

.site-ui .profile-dialog__header h2 {
  font-size: 1.45rem;
  line-height: 1.25;
}

.site-ui .profile-dialog__close {
  width: 44px;
  height: 44px;
  flex: 0 0 44px;
  display: grid;
  place-items: center;
  border: 1px solid transparent;
  border-radius: 16px;
  padding: 0;
  background: transparent;
  box-shadow: none;
  color: var(--muted);
  font-size: 1.55rem;
  font-weight: 400;
  line-height: 1;
}

.site-ui .profile-dialog__close:hover {
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
  color: var(--text);
}

[data-theme="dark"] .site-ui .profile-dialog__close:hover {
  border-color: var(--surface-border);
}

.site-ui .profile-dialog__close:active {
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-pressed);
}

.site-ui .profile-dialog__divider {
  height: 1px;
  margin: 28px 0;
  background: transparent;
  box-shadow: 1px 1px 2px var(--shadow-dark), -1px -1px 2px var(--shadow-light);
}

.site-ui .mobile-experience-notice {
  width: min(420px, calc(100% - 32px));
  margin: auto;
  border: 1px solid var(--surface-border);
  border-radius: 24px;
  padding: 0;
  background: var(--surface-strong);
  color: var(--text);
  box-shadow: var(--dialog-shadow);
  -webkit-backdrop-filter: var(--surface-blur);
  backdrop-filter: var(--surface-blur);
}

.site-ui .mobile-experience-notice::backdrop {
  background: var(--overlay);
  -webkit-backdrop-filter: blur(3px);
  backdrop-filter: blur(3px);
}

.site-ui .mobile-experience-notice__shell {
  padding: 24px;
}

.site-ui .mobile-experience-notice__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.site-ui .mobile-experience-notice h2 {
  margin: 0;
  font-size: 1.28rem;
  line-height: 1.3;
}

.site-ui .mobile-experience-notice p {
  margin: 16px 0 0;
  color: var(--muted);
  line-height: 1.6;
}

.site-ui .mobile-experience-notice__close {
  width: 40px;
  height: 40px;
  flex: 0 0 40px;
  display: grid;
  place-items: center;
  border: 1px solid var(--surface-border);
  border-radius: 12px;
  padding: 0;
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
  color: var(--muted);
  font-size: 1.5rem;
  line-height: 1;
}

.site-ui .mobile-experience-notice__close:hover {
  color: var(--text);
  box-shadow: var(--surface-shadow-hover);
}

.site-ui .mobile-experience-notice__close:active {
  box-shadow: var(--surface-shadow-pressed);
}

[data-theme="dark"] .site-ui .profile-dialog__divider {
  background: linear-gradient(90deg, var(--transparent), var(--surface-border), var(--transparent));
  box-shadow: none;
}

.site-ui .chat-entry {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  text-decoration: none;
}

.site-ui .chat-entry__icon {
  font-size: 1.15rem;
  line-height: 1;
}

.site-ui .chat-entry__label {
  font-size: 0.82rem;
}

.site-ui .chat-entry__badge {
  min-width: 18px;
  padding: 1px 5px;
  border-radius: 999px;
  background: var(--accent);
  color: var(--surface-strong);
  font-size: 0.68rem;
  font-weight: 700;
  text-align: center;
}

.site-ui .chat-shell {
  width: min(1440px, calc(100% - 32px));
  margin: 0 auto;
  padding: 44px 0 72px;
}

.site-ui .chat-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 24px;
}

.site-ui .chat-heading h1 {
  margin: 4px 0 8px;
  font-size: clamp(2rem, 4vw, 3.5rem);
}

.site-ui .chat-heading p:not(.home-eyebrow) {
  max-width: 760px;
  margin: 0;
  color: var(--muted);
}

.site-ui .chat-status {
  min-height: 24px;
  margin: 0;
  color: var(--accent);
  text-align: right;
}

.site-ui .chat-status.is-error {
  color: var(--error);
}

.site-ui .chat-layout {
  display: grid;
  grid-template-columns: minmax(260px, 340px) minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.site-ui .chat-sidebar {
  display: grid;
  gap: 18px;
}

.site-ui .chat-panel {
  border: 1px solid var(--surface-border);
  border-radius: 16px;
  padding: 20px;
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
}

.site-ui .chat-panel--notice {
  max-width: 720px;
}

.site-ui .chat-panel h2 {
  margin: 0;
  font-size: 1.05rem;
}

.site-ui .chat-panel__heading,
.site-ui .chat-conversation-header,
.site-ui .chat-compose__actions,
.site-ui .chat-device-item,
.site-ui .chat-invite-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.site-ui .chat-device-item__actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 6px;
}

.site-ui .chat-device-item__details {
  display: grid;
  min-width: 0;
  gap: 3px;
}

.site-ui .chat-device-item__details strong,
.site-ui .chat-device-item__details small {
  overflow-wrap: anywhere;
}

.site-ui .chat-recovery-actions {
  display: grid;
  gap: 8px;
  margin-top: 12px;
}

.site-ui .chat-setup-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.site-ui .chat-invite-panel > label {
  display: grid;
  gap: 7px;
  margin: 18px 0 10px;
}

.site-ui .chat-invite-panel input,
.site-ui .chat-compose textarea,
.site-ui .chat-retention-control select {
  width: 100%;
  border: 1px solid var(--surface-border);
  border-radius: 10px;
  background: var(--surface-strong);
  color: var(--text);
  padding: 11px 12px;
  font: inherit;
}

.site-ui .chat-invite-list,
.site-ui .chat-device-list {
  display: grid;
  gap: 8px;
  margin-top: 14px;
}

.site-ui .chat-invite-item,
.site-ui .chat-device-item {
  padding-top: 9px;
  border-top: 1px solid var(--surface-border);
  color: var(--muted);
  font-size: 0.78rem;
}

.site-ui .chat-invite-item code {
  max-width: 180px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  color: var(--accent);
}

.site-ui .chat-small-action,
.site-ui .chat-icon-action {
  min-height: 36px;
  padding: 7px 11px;
  font-size: 0.78rem;
}

.site-ui .chat-icon-action {
  min-width: 36px;
  border-radius: 10px;
}

.site-ui .chat-conversation-list {
  display: grid;
  gap: 8px;
  margin-top: 14px;
}

.site-ui .chat-conversation-item {
  display: grid;
  gap: 4px;
  width: 100%;
  border: 1px solid transparent;
  border-radius: 10px;
  padding: 12px;
  background: var(--surface-strong);
  color: var(--text);
  text-align: left;
  cursor: pointer;
}

.site-ui .chat-conversation-item:hover,
.site-ui .chat-conversation-item.is-active {
  border-color: var(--accent);
}

.site-ui .chat-conversation-item small,
.site-ui .chat-muted,
.site-ui .chat-device-item,
.site-ui .chat-retention-control span {
  color: var(--muted);
}

.site-ui .chat-group-create {
  display: grid;
  gap: 10px;
  margin-top: 12px;
  padding: 12px;
  border: 1px solid var(--surface-border);
  border-radius: 10px;
}

.site-ui .chat-group-create p {
  margin: 0;
  font-size: 0.8rem;
}

.site-ui .chat-group-contact-list {
  display: grid;
  gap: 6px;
  max-height: 180px;
  overflow: auto;
}

.site-ui .chat-group-contact-option {
  display: flex;
  gap: 8px;
  align-items: center;
  padding: 6px 8px;
  border-radius: 7px;
  color: var(--text);
}

.site-ui .chat-group-contact-option:hover {
  background: color-mix(in srgb, var(--accent) 10%, transparent);
}

.site-ui .chat-device-fingerprints {
  display: block;
  margin-top: 4px;
  color: var(--muted);
  font-size: 0.72rem;
  overflow-wrap: anywhere;
}

.site-ui .chat-conversation-panel {
  min-height: 640px;
  display: flex;
  flex-direction: column;
}

.site-ui .chat-empty-state {
  display: grid;
  place-items: center;
  align-content: center;
  flex: 1;
  gap: 8px;
  min-height: 560px;
  color: var(--muted);
  text-align: center;
}

.site-ui .chat-empty-state p {
  margin: 0;
}

.site-ui .chat-conversation-header {
  align-items: flex-start;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--surface-border);
}

.site-ui .chat-conversation-header h2 {
  font-size: 1.3rem;
}

.site-ui .chat-conversation-header p {
  margin: 6px 0 0;
  font-size: 0.78rem;
}

.site-ui .chat-retention-control {
  display: grid;
  min-width: 140px;
  gap: 5px;
  font-size: 0.75rem;
}

.site-ui .chat-message-list {
  display: grid;
  align-content: start;
  gap: 10px;
  min-height: 390px;
  max-height: 56vh;
  overflow: auto;
  padding: 18px 4px;
}

.site-ui .chat-message {
  justify-self: start;
  max-width: min(76%, 700px);
  border: 1px solid var(--surface-border);
  border-radius: 12px 12px 12px 4px;
  padding: 10px 12px;
  background: var(--surface-strong);
}

.site-ui .chat-message.is-mine {
  justify-self: end;
  border-radius: 12px 12px 4px 12px;
  background: color-mix(in srgb, var(--accent) 14%, var(--surface-strong));
}

.site-ui .chat-message p,
.site-ui .chat-message time {
  margin: 0;
}

.site-ui .chat-message p {
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.site-ui .chat-message time {
  display: block;
  margin-top: 6px;
  color: var(--muted);
  font-size: 0.68rem;
}

.site-ui .chat-compose {
  position: relative;
  display: grid;
  gap: 10px;
  margin-top: auto;
}

.site-ui .chat-compose textarea {
  resize: vertical;
  min-height: 74px;
}

.site-ui .chat-file-button {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border: 1px solid var(--surface-border);
  border-radius: 10px;
  background: var(--surface-strong);
  color: var(--muted);
  cursor: pointer;
}

.site-ui .chat-file-button:hover {
  color: var(--text);
  border-color: var(--accent);
}

.site-ui .chat-emoji-tray {
  position: absolute;
  bottom: 52px;
  left: 0;
  display: flex;
  gap: 5px;
  border: 1px solid var(--surface-border);
  border-radius: 10px;
  padding: 8px;
  background: var(--surface-strong);
  box-shadow: var(--surface-shadow-small);
}

.site-ui .chat-emoji-tray button {
  border: 0;
  border-radius: 7px;
  padding: 5px;
  background: transparent;
  font-size: 1.1rem;
  cursor: pointer;
}

@media (max-width: 800px) {
  .site-ui .chat-shell {
    width: min(100% - 20px, 680px);
    padding-top: 28px;
  }

  .site-ui .chat-heading {
    display: block;
  }

  .site-ui .chat-status {
    margin-top: 12px;
    text-align: left;
  }

  .site-ui .chat-layout {
    grid-template-columns: 1fr;
  }

  .site-ui .chat-conversation-panel {
    min-height: 520px;
  }

  .site-ui .chat-message-list {
    min-height: 280px;
  }
}

.site-ui .grid-2,
.site-ui .pdf-download-fields {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.site-ui label {
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 500;
}

.site-ui input,
.site-ui select {
  width: 100%;
  min-width: 0;
  min-height: 48px;
  border: 1px solid transparent;
  border-radius: 16px;
  padding: 11px 14px;
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
  color: var(--text);
  font: 500 0.94rem/1.3 "DM Sans", sans-serif;
}

[data-theme="dark"] .site-ui input,
[data-theme="dark"] .site-ui select {
  border-color: var(--surface-border-soft);
  background: var(--glass-well);
}

.site-ui input::placeholder {
  color: var(--placeholder);
}

.site-ui select option {
  background: var(--select-option-bg);
  color: var(--text);
}

.site-ui input:hover,
.site-ui select:hover {
  box-shadow: var(--surface-shadow-deep);
}

.site-ui input:focus,
.site-ui select:focus {
  box-shadow: var(--surface-shadow-deep), 0 0 0 2px var(--accent);
}

.site-ui .actions {
  margin-top: 20px;
}

.site-ui .notebook-mastered-filter,
.site-ui .notebook-star-filter {
  grid-template-columns: 22px minmax(0, 1fr);
  align-items: center;
  align-self: flex-end;
  gap: 10px;
  min-height: 48px;
}

.site-ui .notebook-mastered-filter input[type="checkbox"],
.site-ui .notebook-star-filter input[type="checkbox"] {
  width: 22px;
  min-width: 22px;
  height: 22px;
  min-height: 22px;
  margin: 0;
  padding: 0;
}

.site-ui .pdf-download-dialog {
  width: min(560px, calc(100% - 32px));
}

.site-ui .pdf-download-fields {
  grid-template-columns: 1fr;
}

.site-ui .pdf-download-status {
  min-height: 1.35rem;
  margin: 16px 0 0;
  font-size: 0.86rem;
}

.site-ui .pdf-download-status[hidden] {
  display: none;
}

.site-ui .pdf-download-actions {
  margin-top: 24px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.site-ui .profile-pet-settings {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(160px, 0.55fr);
  gap: 18px;
  align-items: end;
}

.site-ui .profile-pet-settings h3,
.site-ui .profile-pet-settings p {
  margin: 0;
}

.site-ui .profile-pet-settings > .tip {
  grid-column: 1 / -1;
}

.site-ui .setting-toggle {
  min-height: 44px;
  color: var(--text);
}

.site-ui .setting-toggle > input {
  width: 1px;
  min-width: 1px;
  height: 1px;
  min-height: 1px;
  margin: 0;
  padding: 0;
}

.site-ui .setting-toggle > span {
  width: 44px;
  height: 26px;
  border: 1px solid transparent;
  border-radius: 999px;
  background: var(--bg);
  box-shadow: var(--surface-shadow-inset-small);
}

[data-theme="dark"] .site-ui .setting-toggle > span {
  border-color: var(--surface-border-soft);
  background: var(--glass-well);
}

.site-ui .setting-toggle > span::after {
  top: 3px;
  left: 3px;
  width: 20px;
  height: 20px;
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
}

.site-ui .setting-toggle input:checked + span {
  background: var(--bloom-green);
}

[data-theme="dark"] .site-ui .setting-toggle input:checked + span {
  box-shadow: 0 0 12px var(--glow-green);
}

.site-ui .setting-toggle input:checked + span::after {
  transform: translateX(18px);
}

.site-ui .setting-toggle input:focus-visible + span {
  outline: none;
  box-shadow: 0 0 0 2px var(--focus-inner), 0 0 0 4px var(--accent), var(--surface-shadow-inset-small);
}

.site-ui .site-pet__character:focus-visible,
.site-ui button:focus-visible,
.site-ui a:focus-visible,
.site-ui input:focus-visible,
.site-ui select:focus-visible {
  outline: none;
  box-shadow: 0 0 0 2px var(--focus-inner), 0 0 0 4px var(--accent);
}

.site-ui .course-card:focus-visible {
  box-shadow: 0 0 0 2px var(--focus-inner), 0 0 0 4px var(--accent), var(--surface-shadow-hover);
}

.site-ui .site-pet__head,
.site-ui .site-pet__body {
  border: 1px solid transparent;
  background: var(--bg);
  box-shadow: var(--surface-shadow-small);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

[data-theme="dark"] .site-ui .site-pet__head,
[data-theme="dark"] .site-ui .site-pet__body {
  border-color: var(--surface-border);
  background: var(--surface-strong);
  box-shadow: var(--surface-shadow-small);
  -webkit-backdrop-filter: var(--surface-blur);
  backdrop-filter: var(--surface-blur);
}

.site-ui .site-pet__head,
.site-ui .site-pet__body {
  border-radius: 16px;
}

.site-ui .site-pet__head i {
  background: var(--accent);
  box-shadow: 0 0 8px var(--pet-eye-glow);
}

.site-ui .site-pet__head b {
  color: var(--muted);
  font-family: "DM Sans", sans-serif;
}

.site-ui .site-pet__body i {
  border-color: var(--accent);
  border-radius: 12px;
  background: var(--bloom-green-soft);
}

.site-ui .site-pet__antenna {
  background: var(--muted);
}

.site-ui .site-pet__antenna i {
  background: var(--bloom-green);
  box-shadow: 0 0 9px var(--glow-green);
}

.site-ui .site-pet__shadow {
  background: var(--shadow-dark);
}

.site-ui .site-pet__bubble {
  gap: 8px;
  border: 1px solid transparent;
  border-radius: 20px;
  padding: 12px;
  background: var(--bg);
  box-shadow: var(--surface-shadow);
  color: var(--text);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

[data-theme="dark"] .site-ui .site-pet__bubble {
  border-color: var(--surface-border);
  background: var(--surface-strong);
  box-shadow: var(--surface-shadow);
  -webkit-backdrop-filter: var(--surface-blur);
  backdrop-filter: var(--surface-blur);
}

.site-ui .site-pet.has-action .site-pet__bubble {
  border-color: transparent;
  color: var(--accent);
}

[data-theme="dark"] .site-ui .site-pet.has-action .site-pet__bubble {
  border-color: var(--surface-border);
}

.site-ui .site-pet__bubble-message {
  min-height: 44px;
  color: inherit;
}

.site-ui .site-pet__hint-actions {
  display: flex;
  gap: 8px;
  width: 100%;
  padding-right: 32px;
}

.site-ui .site-pet__hint-actions[hidden] {
  display: none !important;
}

.site-ui .site-pet__hint-previous,
.site-ui .site-pet__hint-next {
  min-height: 36px;
  flex: 1 1 0;
  border: 1px solid transparent;
  border-radius: 12px;
  padding: 6px 10px;
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
  color: var(--text);
  font: inherit;
  font-size: .82rem;
  font-weight: 700;
}

.site-ui .site-pet__hint-previous:hover,
.site-ui .site-pet__hint-next:hover {
  background: var(--surface-hover);
}

.site-ui .site-pet__hint-previous:disabled,
.site-ui .site-pet__hint-next:disabled {
  cursor: not-allowed;
  opacity: .45;
}

[data-theme="dark"] .site-ui .site-pet__hint-previous,
[data-theme="dark"] .site-ui .site-pet__hint-next {
  border-color: var(--surface-border);
}

.site-ui .site-pet__bubble-close {
  width: 44px;
  height: 44px;
  flex: 0 0 44px;
  border: 1px solid transparent;
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
  color: var(--muted);
  line-height: 40px;
}

[data-theme="dark"] .site-ui .site-pet__bubble-close {
  border-color: var(--surface-border);
}

@media (max-width: 1023px) {
  .site-ui .course-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 767px) {
  .site-ui .home-topbar__inner,
  .site-ui .home-main {
    width: min(100% - 24px, 1280px);
  }

  .site-ui .home-topbar__inner {
    min-height: 64px;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 12px;
    padding: 8px 0;
  }

  .site-ui .home-brand {
    font-size: 1rem;
  }

  .site-ui .home-brand__mark {
    width: 40px;
    height: 40px;
    flex-basis: 40px;
  }

  .site-ui .home-header-control {
    width: 40px;
    height: 40px;
    min-height: 40px;
    flex-basis: 40px;
  }

  .site-ui .home-menu-toggle {
    display: grid;
  }

  .site-ui .home-nav-actions {
    position: absolute;
    top: calc(100% + 10px);
    right: 12px;
    left: 12px;
    z-index: 31;
    width: auto;
    display: grid;
    grid-template-columns: 1fr;
    gap: 8px;
    border: 1px solid transparent;
    border-radius: 32px;
    padding: 12px;
    background: var(--bg);
    box-shadow: var(--surface-shadow);
    opacity: 0;
    pointer-events: none;
    transform: translateY(-10px);
    visibility: hidden;
  }

  [data-theme="dark"] .site-ui .home-nav-actions {
    border-color: var(--surface-border);
    background: var(--surface-strong);
    -webkit-backdrop-filter: var(--surface-blur);
    backdrop-filter: var(--surface-blur);
  }

  .site-ui .home-nav-actions.is-open {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
    visibility: visible;
  }

  .site-ui .home-nav-button {
    width: 100%;
    min-height: 44px;
    padding-inline: 14px;
    text-align: left;
    white-space: normal;
  }

  .site-ui .home-main {
    min-height: calc(100vh - 64px);
    padding: 48px 0 calc(64px + env(safe-area-inset-bottom));
  }

  .site-ui .home-section-heading {
    margin-bottom: 36px;
    align-items: flex-start;
    flex-direction: column;
    gap: 24px;
  }

  .site-ui .home-section-heading h1 {
    font-size: 2.25rem;
  }

  .site-ui .home-heading-actions {
    width: 100%;
    display: grid;
    grid-template-columns: 1fr;
  }

  .site-ui .home-heading-actions button {
    width: 100%;
  }

  .site-ui .course-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .site-ui .course-card {
    min-height: 0;
    display: grid;
    grid-template-columns: 118px minmax(0, 1fr);
    align-items: center;
    gap: 20px;
    padding: 24px;
  }

  .site-ui .subject-book {
    width: 118px;
    height: 154px;
    flex-basis: 154px;
    margin: 0;
  }

  .site-ui .subject-book__pages {
    top: 5px;
    width: 112px;
    height: 146px;
    border-radius: 12px;
  }

  .site-ui .subject-book__cover {
    width: 112px;
    height: 146px;
    border-radius: 18px;
    padding: 13px 10px 11px 26px;
  }

  .site-ui .subject-book__cover::before {
    top: 12px;
    right: 12px;
    width: 7px;
    height: 7px;
  }

  .site-ui .subject-book__spine {
    width: 17px;
    border-radius: 18px 0 0 18px;
  }

  .site-ui .subject-book__level {
    font-size: 0.5rem;
  }

  .site-ui .subject-book__emblem {
    min-width: 40px;
    min-height: 40px;
    margin-top: 12px;
    border-radius: 12px;
    padding: 6px;
    font-size: 0.8rem;
  }

  .site-ui .subject-book__name {
    margin-top: 8px;
    font-size: 0.67rem;
  }

  .site-ui .subject-book__code {
    padding: 3px 4px;
    font-size: 0.48rem;
  }

  .site-ui .course-card__title {
    font-size: 1rem;
  }

  .site-ui .course-card--loading {
    min-height: 202px;
    display: block;
  }

  .site-ui .profile-dialog {
    max-height: calc(100vh - 16px);
  }

  .site-ui .profile-dialog__shell {
    padding: 20px;
  }

  .site-ui .profile-dialog .grid-2,
  .site-ui .profile-pet-settings,
  .site-ui .pdf-download-actions {
    grid-template-columns: 1fr;
  }

  .site-ui .profile-pet-settings {
    align-items: stretch;
  }

  .site-ui .profile-pet-settings > .tip {
    grid-column: auto;
  }

  .site-ui .site-pet__bubble {
    top: calc(86px + env(safe-area-inset-top));
  }
}

@media (prefers-reduced-motion: reduce) {
  .site-ui *,
  .site-ui *::before,
  .site-ui *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0s !important;
  }
}

/* Shared Meadow Green surfaces */
.site-ui {
  min-height: 100vh;
  overflow-x: clip;
  background: var(--bg);
  color: var(--text);
  font-family: "DM Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  letter-spacing: 0;
}

[data-theme="dark"] .site-ui {
  background:
    radial-gradient(640px 420px at 12% 8%, var(--glow-green), var(--transparent) 60%),
    radial-gradient(520px 520px at 88% 18%, var(--glow-mauve), var(--transparent) 60%),
    radial-gradient(720px 520px at 70% 95%, var(--glow-sky), var(--transparent) 60%),
    radial-gradient(480px 380px at 30% 80%, var(--glow-pink), var(--transparent) 60%),
    var(--bg);
  background-attachment: fixed;
}

.site-ui h1,
.site-ui h2,
.site-ui h3,
.site-ui h4,
.site-ui .home-brand {
  color: var(--text);
  font-family: "Plus Jakarta Sans", "DM Sans", sans-serif;
}

.site-ui .tip,
.site-ui label,
.site-ui .paper-set-meta,
.site-ui .stat-label,
.site-ui .chapter-status,
.site-ui .paper-filter-count {
  color: var(--muted);
}

.site-ui a {
  color: var(--accent);
}

.site-ui .container {
  width: min(1120px, calc(100% - 48px));
  margin: 0 auto;
  padding: 40px 0 calc(64px + env(safe-area-inset-bottom));
  gap: 24px;
}

.site-ui .card,
.site-ui .panel,
.site-ui .paper-picker,
.site-ui .mode-landing,
.site-ui .chapter-practice-workspace,
.site-ui .chapter-band,
.site-ui .community-surface,
.site-ui .community-filter-card,
.site-ui .community-rail-actions {
  min-width: 0;
  border: 1px solid transparent;
  border-radius: 24px;
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow);
  color: var(--text);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

.site-ui .card,
.site-ui .community-surface {
  padding: 24px;
}

[data-theme="dark"] .site-ui .card,
[data-theme="dark"] .site-ui .panel,
[data-theme="dark"] .site-ui .paper-picker,
[data-theme="dark"] .site-ui .mode-landing,
[data-theme="dark"] .site-ui .chapter-practice-workspace,
[data-theme="dark"] .site-ui .chapter-band,
[data-theme="dark"] .site-ui .community-surface,
[data-theme="dark"] .site-ui .community-filter-card,
[data-theme="dark"] .site-ui .community-rail-actions {
  border-color: var(--surface-border);
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow);
  -webkit-backdrop-filter: var(--surface-blur);
  backdrop-filter: var(--surface-blur);
}

.site-ui .question,
.site-ui .option-item,
.site-ui .stat-card,
.site-ui .review-answer-table-card,
.site-ui .review-chart-card,
.site-ui .question-context,
.site-ui .paper-set-item,
.site-ui .mode-option-card,
.site-ui .paper-reference-preview {
  min-width: 0;
  border: 1px solid transparent;
  border-radius: 18px;
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
  color: var(--text);
}

[data-theme="dark"] .site-ui .question,
[data-theme="dark"] .site-ui .option-item,
[data-theme="dark"] .site-ui .stat-card,
[data-theme="dark"] .site-ui .review-answer-table-card,
[data-theme="dark"] .site-ui .review-chart-card,
[data-theme="dark"] .site-ui .question-context,
[data-theme="dark"] .site-ui .paper-set-item,
[data-theme="dark"] .site-ui .mode-option-card,
[data-theme="dark"] .site-ui .paper-reference-preview {
  border-color: var(--surface-border-soft);
  background: var(--glass-well);
  box-shadow: var(--surface-shadow-deep);
}

.site-ui .question-image,
.site-ui .review-question-image,
.site-ui .discussion-question-reference img,
.site-ui .markdown-body img {
  max-width: 100%;
  border-color: var(--surface-border-soft);
  background: var(--bg);
}

/* Persistent navigation and controls */
.site-ui .site-topbar,
.site-ui .chapter-topbar,
.site-ui .community-topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  min-height: 68px;
  border: 1px solid transparent;
  border-width: 0 0 1px;
  padding-top: env(safe-area-inset-top);
  background: var(--bg);
  box-shadow: 9px 9px 16px var(--shadow-dark), -9px -9px 16px var(--shadow-light);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

[data-theme="dark"] .site-ui .site-topbar,
[data-theme="dark"] .site-ui .chapter-topbar,
[data-theme="dark"] .site-ui .community-topbar {
  border-color: var(--surface-border);
  background: var(--surface-strong);
  box-shadow: var(--surface-shadow);
  -webkit-backdrop-filter: var(--surface-blur);
  backdrop-filter: var(--surface-blur);
}

.site-ui .site-topbar__inner,
.site-ui .chapter-topbar,
.site-ui .community-topbar__inner {
  width: min(1180px, calc(100% - 48px));
  min-height: 68px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 16px;
}

.site-ui .site-topbar__inner,
.site-ui .chapter-topbar {
  justify-content: space-between;
}

.site-ui .community-topbar__inner {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
}

.site-ui .site-header-controls,
.site-ui .community-topbar__actions,
.site-ui .home-header-controls {
  min-width: 0;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 6px;
}

.site-ui .site-header-control,
.site-ui .language-toggle {
  position: relative;
  inset: auto;
  z-index: auto;
  width: auto;
  min-width: 44px;
  height: 44px;
  min-height: 44px;
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  border: 1px solid transparent;
  border-radius: 16px;
  padding: 0 12px;
  background: transparent;
  box-shadow: none;
  color: var(--muted);
  font: 700 0.78rem/1 "DM Sans", sans-serif;
  cursor: pointer;
}

.site-ui .home-theme-toggle {
  width: 44px;
  padding: 0;
}

.site-ui .site-header-control:hover,
.site-ui .site-header-control:focus-visible,
.site-ui .language-toggle:hover,
.site-ui .language-toggle:focus-visible {
  border-color: transparent;
  background: var(--bg);
  box-shadow: var(--surface-shadow-small);
  color: var(--text);
  transform: translateY(-1px);
}

[data-theme="dark"] .site-ui .site-header-control:hover,
[data-theme="dark"] .site-ui .site-header-control:focus-visible,
[data-theme="dark"] .site-ui .language-toggle:hover,
[data-theme="dark"] .site-ui .language-toggle:focus-visible {
  border-color: var(--surface-border);
  background: var(--surface-raised);
}

.site-ui .site-header-control:active,
.site-ui .language-toggle:active {
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-pressed);
  transform: translateY(0);
}

.site-ui .home-theme-icon {
  position: absolute;
  width: 22px;
  height: 22px;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
  transition: transform 0.4s cubic-bezier(0.45, 0, 0.25, 1), opacity 0.3s ease-out;
}

.site-ui .home-theme-icon--sun {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

.site-ui .home-theme-icon--moon {
  opacity: 0;
  transform: rotate(-90deg) scale(0.6);
}

[data-theme="dark"] .site-ui .home-theme-icon--sun {
  opacity: 0;
  transform: rotate(90deg) scale(0.6);
}

[data-theme="dark"] .site-ui .home-theme-icon--moon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

.site-ui button,
.site-ui .btn-link,
.site-ui .mode-btn-primary,
.site-ui .mode-btn-secondary,
.site-ui .paper-set-btn,
.site-ui .pdf-download-action {
  min-height: 44px;
  border: 1px solid transparent;
  border-radius: 16px;
  font-family: "DM Sans", sans-serif;
  font-weight: 700;
}

.site-ui .btn-primary,
.site-ui .mode-btn-primary,
.site-ui .paper-set-btn.start,
.site-ui .pdf-download-action {
  background: var(--accent);
  color: var(--primary-text);
  box-shadow: 7px 7px 14px var(--btn-accent-shadow-dark), -7px -7px 14px var(--btn-accent-shadow-light);
}

[data-theme="dark"] .site-ui .btn-primary,
[data-theme="dark"] .site-ui .mode-btn-primary,
[data-theme="dark"] .site-ui .paper-set-btn.start,
[data-theme="dark"] .site-ui .pdf-download-action {
  border-color: var(--surface-border);
  box-shadow: 0 8px 24px var(--glow-green);
}

.site-ui .btn-secondary,
.site-ui .btn-link,
.site-ui .mode-btn-secondary,
.site-ui .paper-set-btn.retry,
.site-ui .pdf-download-action--answer {
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
  color: var(--text);
}

[data-theme="dark"] .site-ui .btn-secondary,
[data-theme="dark"] .site-ui .btn-link,
[data-theme="dark"] .site-ui .mode-btn-secondary,
[data-theme="dark"] .site-ui .paper-set-btn.retry,
[data-theme="dark"] .site-ui .pdf-download-action--answer {
  border-color: var(--surface-border);
}

.site-ui .btn-primary:hover,
.site-ui .mode-btn-primary:hover,
.site-ui .paper-set-btn.start:hover,
.site-ui .pdf-download-action:hover {
  background: var(--accent-light);
  transform: translateY(-1px);
}

.site-ui .btn-secondary:hover,
.site-ui .btn-link:hover,
.site-ui .mode-btn-secondary:hover,
.site-ui .paper-set-btn.retry:hover,
.site-ui .pdf-download-action--answer:hover {
  background: var(--surface-hover);
  box-shadow: var(--surface-shadow-hover);
  color: var(--text);
  transform: translateY(-1px);
}

.site-ui button:active,
.site-ui .btn-link:active {
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-pressed);
  color: var(--text);
  transform: translateY(0);
}

.site-ui button:disabled,
.site-ui .is-disabled {
  cursor: not-allowed;
  box-shadow: none;
  opacity: 0.45;
  transform: none;
}

.site-ui button:focus-visible,
.site-ui a:focus-visible,
.site-ui input:focus-visible,
.site-ui select:focus-visible,
.site-ui textarea:focus-visible,
.site-ui summary:focus-visible,
.site-ui [contenteditable="true"]:focus-visible {
  outline: 2px solid var(--focus-inner);
  outline-offset: 2px;
  box-shadow: 0 0 0 4px var(--accent);
}

.site-ui label,
.site-ui .grid-2 > *,
.site-ui .pdf-download-fields > * {
  min-width: 0;
  max-width: 100%;
}

.site-ui input,
.site-ui select,
.site-ui textarea,
.site-ui .rich-text-editor {
  width: 100%;
  max-width: 100%;
  min-width: 0;
  min-height: 48px;
  border: 1px solid transparent;
  border-radius: 16px;
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
  color: var(--text);
}

[data-theme="dark"] .site-ui input,
[data-theme="dark"] .site-ui select,
[data-theme="dark"] .site-ui textarea,
[data-theme="dark"] .site-ui .rich-text-editor {
  border-color: var(--surface-border-soft);
  background: var(--glass-well);
}

.site-ui input.is-invalid,
.site-ui select.is-invalid,
.site-ui textarea.is-invalid,
.site-ui .rich-text-editor.is-invalid {
  border-color: var(--error);
  box-shadow: var(--surface-shadow-deep), 0 0 0 2px var(--error);
}

.site-ui select option {
  background: var(--select-option-bg);
  color: var(--text);
}

/* Independent secondary interfaces */
.site-ui .profile-dialog {
  overflow-x: hidden;
  overflow-y: auto;
  box-shadow: var(--floating-shadow);
}

.site-ui .profile-dialog__shell,
.site-ui .profile-dialog .grid-2,
.site-ui .profile-dialog label,
.site-ui .profile-dialog input,
.site-ui .profile-dialog select {
  min-width: 0;
  max-width: 100%;
}

.site-ui .profile-dialog__close,
.site-ui .math-keyboard-close {
  width: 44px;
  height: 44px;
  min-height: 44px;
  flex: 0 0 44px;
  display: grid;
  place-items: center;
  border: 1px solid transparent;
  border-radius: 16px;
  padding: 0;
  background: transparent;
  box-shadow: none;
  color: var(--muted);
  font-size: 1.55rem;
  font-weight: 400;
  line-height: 1;
}

.site-ui .profile-dialog__close:hover,
.site-ui .math-keyboard-close:hover {
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
  color: var(--text);
}

[data-theme="dark"] .site-ui .profile-dialog__close:hover,
[data-theme="dark"] .site-ui .math-keyboard-close:hover {
  border-color: var(--surface-border);
}

.site-ui .profile-dialog__close:active,
.site-ui .math-keyboard-close:active {
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-pressed);
}

.site-ui .community-filter-card,
.site-ui .math-input-panel,
.site-ui .formatting-toolbar,
.site-ui .rich-editor-math-menu-list,
.site-ui .community-toast,
.site-ui .site-pet__bubble,
.site-ui .home-nav-actions.is-open {
  overflow-x: hidden;
  border: 1px solid transparent;
  background: var(--bg);
  box-shadow: var(--floating-shadow);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

[data-theme="dark"] .site-ui .community-filter-card,
[data-theme="dark"] .site-ui .math-input-panel,
[data-theme="dark"] .site-ui .formatting-toolbar,
[data-theme="dark"] .site-ui .rich-editor-math-menu-list,
[data-theme="dark"] .site-ui .community-toast,
[data-theme="dark"] .site-ui .site-pet__bubble,
[data-theme="dark"] .site-ui .home-nav-actions.is-open {
  border-color: var(--surface-border);
  background: var(--surface-strong);
  box-shadow: var(--floating-shadow);
  -webkit-backdrop-filter: var(--surface-blur);
  backdrop-filter: var(--surface-blur);
}

.site-ui .math-input-panel {
  overflow-y: auto;
}

.site-ui .formatting-toolbar,
.site-ui .rich-editor-math-menu-list {
  border-radius: 16px;
}

.site-ui .community-toast {
  grid-template-columns: minmax(0, 1fr) 44px;
  border-radius: 18px;
  padding: 14px;
  color: var(--error);
}

.site-ui .community-toast.is-success {
  color: var(--accent-teal);
}

.site-ui .community-toast button {
  width: 44px;
  min-height: 44px;
  border-radius: 14px;
  color: currentColor;
}

/* Community structure retained under the canonical design system */
.site-ui.community-page [hidden] {
  display: none !important;
}

.site-ui .community-topbar__title {
  min-width: 0;
  display: grid;
  gap: 2px;
}

.site-ui .community-topbar__title span {
  overflow: hidden;
  color: var(--muted);
  font-size: 0.78rem;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.site-ui .community-shell {
  width: min(1180px, calc(100% - 48px));
  margin: 0 auto;
  padding: 28px 0 calc(64px + env(safe-area-inset-bottom));
}

.site-ui .community-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 24px;
  align-items: start;
}

.site-ui .community-main {
  min-width: 0;
  display: grid;
  gap: 24px;
}

.site-ui .community-toolbar,
.site-ui .community-view-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.site-ui .community-rail {
  position: sticky;
  top: calc(84px + env(safe-area-inset-top));
  display: grid;
  gap: 16px;
}

.site-ui .community-rail-actions {
  display: flex;
  gap: 10px;
  padding: 14px;
}

.site-ui .community-rail-actions button {
  flex: 1 1 0;
}

.site-ui .community-filter-card > summary {
  display: none;
}

.site-ui .community-filter-body {
  display: grid;
  gap: 12px;
  padding: 18px;
}

.site-ui .community-filter-body .actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
}

.site-ui .discussion-list {
  gap: 0;
  margin: 12px -24px -24px;
}

.site-ui .discussion-thread {
  border: 0;
  border-top: 1px solid var(--surface-border-soft);
  border-radius: 0;
  background: transparent;
  padding: 20px 24px;
}

.site-ui .discussion-thread:hover {
  background: var(--surface-hover);
}

.site-ui .discussion-post {
  border: 0;
  border-bottom: 1px solid var(--surface-border-soft);
  border-radius: 0;
  background: transparent;
  padding: 20px 0;
}

.site-ui .rich-text-editor {
  min-height: 190px;
}

.site-ui .math-input-panel {
  position: sticky;
  bottom: 12px;
  z-index: 70;
  margin-top: 0;
  border-radius: 24px;
}

.site-ui .community-toast-region {
  position: fixed;
  top: calc(84px + env(safe-area-inset-top));
  right: max(20px, env(safe-area-inset-right));
  z-index: 100;
  width: min(390px, calc(100% - 40px));
  pointer-events: none;
}

.site-ui .community-toast {
  pointer-events: auto;
}

/* Wide data tables are the only sanctioned horizontal scrolling surface. */
.site-ui .table-wrap {
  max-width: 100%;
  overflow-x: auto;
  overscroll-behavior-inline: contain;
}

@media (max-width: 900px) {
  .site-ui .community-topbar__title {
    display: none;
  }

  .site-ui .community-topbar__inner {
    grid-template-columns: minmax(0, 1fr) auto;
  }

  .site-ui .community-layout {
    grid-template-columns: 1fr;
  }

  .site-ui .community-main {
    grid-row: 2;
  }

  .site-ui .community-rail {
    position: static;
    grid-row: 1;
  }

  .site-ui .community-filter-card > summary {
    min-height: 48px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 16px;
    color: var(--text);
    font-weight: 700;
    list-style: none;
  }

  .site-ui .community-filter-card > summary::after {
    content: "+";
    color: var(--accent);
    font-size: 1.2rem;
  }

  .site-ui .community-filter-card[open] > summary::after {
    content: "\2212";
  }

  .site-ui .community-filter-card > summary::-webkit-details-marker {
    display: none;
  }

  .site-ui .community-filter-card:not([open]) .community-filter-body {
    display: none;
  }
}

@media (max-width: 620px) {
  .site-ui .container,
  .site-ui .site-topbar__inner,
  .site-ui .chapter-topbar,
  .site-ui .community-topbar__inner,
  .site-ui .community-shell {
    width: min(100% - 24px, 1180px);
  }

  .site-ui .container {
    padding-top: 24px;
  }

  .site-ui .card,
  .site-ui .community-surface {
    padding: 18px;
  }

  .site-ui .grid-2,
  .site-ui .profile-dialog .grid-2 {
    grid-template-columns: 1fr;
  }

  .site-ui .community-topbar__actions {
    gap: 4px;
  }

  .site-ui .community-topbar__actions #communityLogout {
    display: none;
  }

  .site-ui .community-toolbar,
  .site-ui .community-view-heading,
  .site-ui .discussion-detail-head,
  .site-ui .moderation-row {
    align-items: stretch;
    flex-direction: column;
  }

  .site-ui .discussion-list {
    margin: 8px -18px -18px;
  }

  .site-ui .discussion-thread {
    padding: 18px;
  }

  .site-ui .math-input-panel {
    position: fixed;
    right: 12px;
    bottom: max(12px, env(safe-area-inset-bottom));
    left: 12px;
    max-height: min(62vh, 520px);
    overflow-x: hidden;
    overflow-y: auto;
  }

  .site-ui .community-toast-region {
    top: calc(74px + env(safe-area-inset-top));
    right: 12px;
    width: calc(100% - 24px);
  }
}

/* Elevated pet and dock-dismiss feedback */
.site-ui .site-pet {
  filter: drop-shadow(0 14px 14px var(--shadow-dark-heavy));
}

[data-theme="dark"] .site-ui .site-pet {
  filter: drop-shadow(0 18px 18px var(--glass-shadow-color));
}

.site-ui .site-pet__head,
.site-ui .site-pet__body {
  border-color: transparent;
  background: var(--bg);
  box-shadow: var(--surface-shadow-small);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

[data-theme="dark"] .site-ui .site-pet__head,
[data-theme="dark"] .site-ui .site-pet__body {
  border-color: var(--surface-border);
  background: var(--surface-strong);
  box-shadow: var(--surface-shadow);
  -webkit-backdrop-filter: var(--surface-blur);
  backdrop-filter: var(--surface-blur);
}

.site-ui .site-pet__head i {
  background: var(--accent-light);
  box-shadow: 0 0 8px var(--pet-eye-glow);
}

.site-ui .site-pet__head b,
.site-ui .site-pet__bubble {
  color: var(--text);
}

.site-ui .site-pet__body i {
  border-color: var(--accent);
  background: var(--bloom-green-soft);
}

.site-ui .site-pet__antenna {
  background: var(--muted);
}

.site-ui .site-pet__antenna i {
  background: var(--accent-teal);
  box-shadow: 0 0 9px var(--glow-green);
}

.site-ui .site-pet__shadow {
  width: 62px;
  height: 10px;
  background: var(--shadow-dark-heavy);
  filter: blur(5px);
  opacity: 0.72;
}

.site-ui .site-pet__bubble {
  position: absolute;
  right: 74px;
  bottom: 56px;
  width: max-content;
  max-width: min(300px, calc(100vw - 132px));
  min-height: 64px;
  display: block;
  border-radius: 18px;
  padding: 16px 52px 16px 18px;
  font-size: 13px;
  line-height: 1.45;
}

.site-ui .site-pet[data-dock-side="left"] .site-pet__bubble {
  right: auto;
  left: 74px;
}

.site-ui .site-pet__bubble-message {
  width: 100%;
  min-height: 32px;
}

.site-ui .site-pet__bubble[hidden] {
  display: none !important;
}

.site-ui .site-pet__bubble-close {
  position: absolute;
  top: 0;
  right: 0;
  width: 44px;
  height: 44px;
  min-height: 44px;
  display: grid;
  place-items: center;
  border: 0;
  border-radius: 0 18px 0 44px;
  padding: 0 0 8px 8px;
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-pressed);
  color: var(--muted);
  font-size: 18px;
  line-height: 1;
}

.site-ui .site-pet__bubble-close:hover {
  background: var(--surface-hover);
  color: var(--text);
}

[data-theme="dark"] .site-ui .site-pet__bubble-close {
  border: 1px solid var(--surface-border-soft);
  border-width: 0 0 1px 1px;
}

.site-ui .setting-toggle > span {
  border-color: transparent;
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
}

[data-theme="dark"] .site-ui .setting-toggle > span {
  border-color: var(--surface-border-soft);
  background: var(--glass-well);
}

.site-ui .setting-toggle > span::after {
  background: var(--text);
  box-shadow: var(--surface-shadow-small);
}

.site-ui .setting-toggle input:checked + span {
  background: var(--accent);
}

@media (max-width: 640px) {
  .site-ui .site-pet__bubble,
  .site-ui .site-pet[data-dock-side="left"] .site-pet__bubble {
    position: fixed;
    top: calc(86px + env(safe-area-inset-top));
    right: max(12px, env(safe-area-inset-right));
    left: max(12px, env(safe-area-inset-left));
    bottom: auto;
    width: auto;
    max-width: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .site-ui .site-pet__character,
  .site-ui .site-pet__antenna i {
    animation: none !important;
  }
}

/* Canonical header geometry and content boundaries */
.site-ui .home-topbar,
.site-ui .site-topbar,
.site-ui .chapter-topbar,
.site-ui .community-topbar {
  width: 100%;
  min-height: calc(72px + env(safe-area-inset-top));
  margin: 0;
}

.site-ui .chapter-topbar {
  padding-right: 0;
  padding-left: 0;
}

.site-ui .home-topbar__inner,
.site-ui .site-topbar__inner,
.site-ui .chapter-topbar__inner,
.site-ui .community-topbar__inner {
  width: min(1180px, calc(100% - 48px));
  min-height: 72px;
  margin: 0 auto;
  padding: 0;
}

.site-ui .home-topbar__inner,
.site-ui .site-topbar__inner,
.site-ui .chapter-topbar__inner {
  display: grid;
  align-items: center;
  gap: 20px;
}

.site-ui .home-topbar__inner {
  grid-template-columns: auto minmax(0, 1fr) auto;
}

.site-ui .site-topbar__inner,
.site-ui .chapter-topbar__inner {
  grid-template-columns: minmax(0, 1fr) auto;
}

.site-ui .community-topbar__inner {
  gap: 20px;
}

.site-ui .home-brand {
  min-width: 0;
  max-width: 100%;
}

.site-ui .home-brand > span:last-child,
.site-ui .community-topbar__title,
.site-ui .community-topbar__title strong,
.site-ui .community-topbar__title span {
  min-width: 0;
  max-width: 100%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.site-ui .site-header-controls,
.site-ui .home-header-controls,
.site-ui .community-topbar__actions {
  min-width: 0;
  max-width: 100%;
  flex-wrap: nowrap;
}

.site-ui .site-header-command {
  max-width: 12rem;
  min-height: 44px;
  padding: 10px 14px;
  overflow-wrap: anywhere;
  white-space: normal;
}

.site-ui :where(
  .card,
  .panel,
  .community-surface,
  .community-filter-card,
  .community-filter-body,
  .community-rail-actions,
  .profile-dialog__shell,
  .paper-picker-head,
  .paper-filter-bar,
  .paper-set-item,
  .mode-landing-copy,
  .mode-summary-row,
  .mode-option-card,
  .chapter-heading,
  .chapter-band,
  .chapter-section-row,
  .chapter-practice-toolbar,
  .chapter-question-actions,
  .community-toolbar,
  .community-view-heading,
  .markdown-editor-head,
  .math-input-head,
  .math-input-footer,
  .actions,
  .grid-2
) > * {
  min-width: 0;
  max-width: 100%;
}

.site-ui :where(
  h1,
  h2,
  h3,
  h4,
  p,
  label,
  button,
  .btn-link,
  .tip,
  .thread-title-button,
  .discussion-post,
  .markdown-body,
  .mode-option-copy,
  .mode-summary-row > span
) {
  max-width: 100%;
  overflow-wrap: anywhere;
}

.site-ui button,
.site-ui .btn-link {
  min-width: 0;
  white-space: normal;
}

.site-ui .actions,
.site-ui .paper-picker-head,
.site-ui .paper-filter-bar,
.site-ui .chapter-heading,
.site-ui .chapter-practice-toolbar,
.site-ui .chapter-question-actions,
.site-ui .community-toolbar,
.site-ui .community-view-heading,
.site-ui .markdown-editor-head,
.site-ui .math-input-head,
.site-ui .math-input-footer {
  flex-wrap: wrap;
}

.site-ui .profile-dialog,
.site-ui .pdf-download-dialog,
.site-ui .home-nav-actions.is-open,
.site-ui .community-filter-card,
.site-ui .math-input-panel,
.site-ui .formatting-toolbar,
.site-ui .rich-editor-math-menu-list,
.site-ui .community-toast,
.site-ui .site-pet__bubble {
  isolation: isolate;
  box-shadow: var(--floating-shadow);
}

.site-ui .profile-dialog,
.site-ui .pdf-download-dialog {
  margin-block: auto;
}

@media (max-width: 767px) {
  .site-ui .home-topbar,
  .site-ui .site-topbar,
  .site-ui .chapter-topbar,
  .site-ui .community-topbar {
    min-height: calc(64px + env(safe-area-inset-top));
  }

  .site-ui .home-topbar__inner,
  .site-ui .site-topbar__inner,
  .site-ui .chapter-topbar__inner,
  .site-ui .community-topbar__inner {
    width: calc(100% - 24px);
    min-height: 64px;
    gap: 8px;
  }

  .site-ui .home-brand {
    gap: 8px;
  }

  .site-ui .home-brand__mark {
    width: 40px;
    height: 40px;
    flex-basis: 40px;
  }

  .site-ui #timerDisplay {
    position: static;
    width: max-content;
    max-width: 100%;
  }

  .site-ui .site-header-controls,
  .site-ui .home-header-controls,
  .site-ui .community-topbar__actions {
    gap: 2px;
  }

  .site-ui .site-header-command {
    max-width: 7.5rem;
    padding-inline: 9px;
    font-size: 0.78rem;
  }
}

@media (max-width: 430px) {
  .site-ui .site-header-command {
    width: 44px;
    max-width: 44px;
    overflow: hidden;
    padding-inline: 5px;
    font-size: 0.68rem;
    line-height: 1.05;
  }

  .site-ui .home-brand > span:last-child {
    display: none;
  }
}

/* Floating liquid-glass navigation and readable administrator details */
.site-ui .home-topbar,
.site-ui .site-topbar,
.site-ui .chapter-topbar,
.site-ui .community-topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  min-height: calc(82px + env(safe-area-inset-top));
  padding: calc(10px + env(safe-area-inset-top)) 0 8px;
  border: 0;
  background: transparent;
  box-shadow: none;
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

[data-theme="dark"] .site-ui .home-topbar,
[data-theme="dark"] .site-ui .site-topbar,
[data-theme="dark"] .site-ui .chapter-topbar,
[data-theme="dark"] .site-ui .community-topbar {
  border-color: transparent;
  background: transparent;
  box-shadow: none;
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

.site-ui .home-topbar__inner,
.site-ui .site-topbar__inner,
.site-ui .chapter-topbar__inner,
.site-ui .community-topbar__inner {
  position: relative;
  isolation: isolate;
  width: min(1180px, calc(100% - 32px));
  min-height: 64px;
  margin: 0 auto;
  padding: 8px 12px;
  border: 1px solid rgba(255, 255, 255, 0.72);
  border-radius: 28px;
  background: rgba(238, 245, 240, 0.88);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.86),
    inset 0 -1px 0 rgba(77, 103, 87, 0.16),
    0 5px 14px rgba(78, 101, 86, 0.12),
    0 18px 44px rgba(66, 88, 73, 0.16);
}

@supports ((-webkit-backdrop-filter: blur(1px)) or (backdrop-filter: blur(1px))) {
  .site-ui .home-topbar__inner,
  .site-ui .site-topbar__inner,
  .site-ui .chapter-topbar__inner,
  .site-ui .community-topbar__inner {
    background: rgba(238, 245, 240, 0.46);
    -webkit-backdrop-filter: blur(26px) saturate(180%) contrast(108%);
    backdrop-filter: blur(26px) saturate(180%) contrast(108%);
  }
}

[data-theme="dark"] .site-ui .home-topbar__inner,
[data-theme="dark"] .site-ui .site-topbar__inner,
[data-theme="dark"] .site-ui .chapter-topbar__inner,
[data-theme="dark"] .site-ui .community-topbar__inner {
  border-color: rgba(255, 255, 255, 0.24);
  background: rgba(24, 30, 33, 0.88);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.28),
    inset 0 -1px 0 rgba(0, 0, 0, 0.42),
    0 6px 18px rgba(0, 0, 0, 0.2),
    0 22px 52px rgba(0, 0, 0, 0.34);
}

@supports ((-webkit-backdrop-filter: blur(1px)) or (backdrop-filter: blur(1px))) {
  [data-theme="dark"] .site-ui .home-topbar__inner,
  [data-theme="dark"] .site-ui .site-topbar__inner,
  [data-theme="dark"] .site-ui .chapter-topbar__inner,
  [data-theme="dark"] .site-ui .community-topbar__inner {
    background: rgba(24, 30, 33, 0.5);
  }
}

.site-ui .home-topbar__inner::before,
.site-ui .site-topbar__inner::before,
.site-ui .chapter-topbar__inner::before,
.site-ui .community-topbar__inner::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  border-radius: inherit;
  background: linear-gradient(
    116deg,
    rgba(255, 255, 255, 0.42) 0%,
    rgba(255, 255, 255, 0.08) 38%,
    rgba(143, 190, 166, 0.12) 68%,
    rgba(255, 255, 255, 0.28) 100%
  );
  clip-path: inset(0 round 28px);
  pointer-events: none;
}

.site-ui .home-topbar__inner > *,
.site-ui .site-topbar__inner > *,
.site-ui .chapter-topbar__inner > *,
.site-ui .community-topbar__inner > * {
  position: relative;
  z-index: 1;
}

.site-ui .community-toast-region {
  top: calc(92px + env(safe-area-inset-top));
}

.site-ui .community-topbar__actions > .site-header-command,
.site-ui .community-topbar__actions > #communityLogout {
  min-height: 44px;
  padding: 10px 14px;
}

.site-ui .admin-detail-dialog {
  width: min(1100px, calc(100vw - 32px));
  max-height: calc(100vh - 32px);
  margin: auto;
  padding: 0;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.72);
  border-radius: 8px;
  background: rgba(236, 242, 237, 0.94);
  color: var(--text);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.88),
    0 30px 80px rgba(30, 44, 35, 0.34);
  -webkit-backdrop-filter: blur(32px) saturate(145%);
  backdrop-filter: blur(32px) saturate(145%);
}

[data-theme="dark"] .site-ui .admin-detail-dialog {
  border-color: rgba(255, 255, 255, 0.2);
  background: rgba(27, 32, 35, 0.94);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.22),
    0 32px 88px rgba(0, 0, 0, 0.62);
}

.site-ui .admin-detail-dialog::backdrop {
  background: rgba(18, 27, 23, 0.58);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}

.site-ui .admin-detail-dialog__shell {
  max-height: calc(100vh - 34px);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.site-ui .admin-detail-dialog__header {
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 18px;
  border-bottom: 1px solid rgba(66, 88, 73, 0.18);
  background: rgba(245, 249, 246, 0.62);
}

[data-theme="dark"] .site-ui .admin-detail-dialog__header {
  border-bottom-color: rgba(255, 255, 255, 0.12);
  background: rgba(17, 21, 23, 0.5);
}

.site-ui .admin-detail-dialog__header h2 {
  margin: 0;
  font-size: 1.25rem;
  line-height: 1.25;
}

.site-ui .admin-detail-dialog__body {
  min-height: 0;
  padding: 18px;
  overflow: auto;
  overscroll-behavior: contain;
}

.site-ui .admin-detail-dialog__body > :first-child {
  margin-top: 0;
}

.site-ui .admin-import-dialog-actions {
  margin-bottom: 18px;
}

@media (max-width: 767px) {
  .site-ui .home-topbar,
  .site-ui .site-topbar,
  .site-ui .chapter-topbar,
  .site-ui .community-topbar {
    min-height: calc(72px + env(safe-area-inset-top));
    padding: calc(8px + env(safe-area-inset-top)) 0 6px;
  }

  .site-ui .home-topbar__inner,
  .site-ui .site-topbar__inner,
  .site-ui .chapter-topbar__inner,
  .site-ui .community-topbar__inner {
    width: calc(100% - 16px);
    min-height: 58px;
    gap: 8px;
    padding: 6px 8px;
    border-radius: 24px;
  }

  .site-ui .home-topbar__inner::before,
  .site-ui .site-topbar__inner::before,
  .site-ui .chapter-topbar__inner::before,
  .site-ui .community-topbar__inner::before {
    clip-path: inset(0 round 24px);
  }

  .site-ui .home-nav-actions {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    left: 0;
  }

  .site-ui .community-topbar__actions > .site-header-command {
    width: auto;
    max-width: 7.5rem;
    height: 44px;
    padding-inline: 9px;
    overflow: visible;
    font-size: 0.78rem;
    white-space: nowrap;
  }

  .site-ui .home-brand > span:last-child {
    display: inline;
  }

  .site-ui .community-toast-region {
    top: calc(80px + env(safe-area-inset-top));
  }

  .site-ui .site-pet__bubble,
  .site-ui .site-pet[data-dock-side="left"] .site-pet__bubble {
    top: calc(82px + env(safe-area-inset-top));
  }

  .site-ui .admin-detail-dialog {
    width: calc(100vw - 16px);
    max-height: calc(100vh - 16px);
  }

  .site-ui .admin-detail-dialog__shell {
    max-height: calc(100vh - 18px);
  }

  .site-ui .admin-detail-dialog__header {
    min-height: 60px;
    padding: 10px 12px;
  }

  .site-ui .admin-detail-dialog__body {
    padding: 14px 12px;
  }
}

/* Mobile home shortcuts and dark practice surfaces. */
.site-ui .home-mobile-shortcuts {
  display: none;
}

[data-theme="dark"] .site-ui .paper-set-btn.start,
[data-theme="dark"] .site-ui .mode-btn-primary {
  background: #78ad7f;
  color: #0f1f15;
}

[data-theme="dark"] .site-ui .paper-filter-bar {
  border-color: var(--surface-border-soft);
  background: var(--glass-well);
}

[data-theme="dark"] .site-ui .paper-filter-bar label,
[data-theme="dark"] .site-ui .paper-filter-count,
[data-theme="dark"] .site-ui .paper-set-title,
[data-theme="dark"] .site-ui .paper-set-meta {
  color: var(--text);
}

[data-theme="dark"] .site-ui .paper-set-icon.idle,
[data-theme="dark"] .site-ui .paper-set-icon.done {
  border: 1px solid var(--surface-border-soft);
  background: var(--surface-strong);
  color: var(--accent);
}

[data-theme="dark"] .site-ui .question-side,
[data-theme="dark"] .site-ui .jump-btn,
[data-theme="dark"] .site-ui .question-star-btn,
[data-theme="dark"] .site-ui .tag {
  border-color: var(--surface-border-soft);
  background: var(--glass-well);
  color: var(--text);
}

[data-theme="dark"] .site-ui .question-side-title {
  color: var(--accent);
}

[data-theme="dark"] .site-ui .jump-btn.active {
  border-color: var(--accent);
  background: #315d43;
  color: #f4f7f5;
}

[data-theme="dark"] .site-ui .question-star-btn.is-starred {
  border-color: #d7b65d;
  background: rgba(215, 182, 93, 0.16);
  color: #f0cf78;
}

@media (max-width: 767px) {
  .site-ui .home-mobile-shortcuts {
    position: relative;
    z-index: 20;
    width: calc(100% - 24px);
    min-height: 48px;
    margin: 10px auto 0;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
    border: 1px solid transparent;
    border-radius: 18px;
    padding: 5px;
    background: var(--bg);
    box-shadow: var(--surface-shadow-small);
  }

  [data-theme="dark"] .site-ui .home-mobile-shortcuts {
    border-color: var(--surface-border);
    background: #20252a;
  }

  .site-ui .home-mobile-shortcuts a {
    min-width: 0;
    min-height: 36px;
    display: grid;
    place-items: center;
    border-radius: 13px;
    color: var(--text);
    font: 700 0.86rem/1.2 "DM Sans", sans-serif;
    text-decoration: none;
  }

  .site-ui .home-mobile-shortcuts a:hover,
  .site-ui .home-mobile-shortcuts a:focus-visible {
    background: var(--surface-hover);
  }

  .site-ui .home-mobile-shortcuts a[hidden] + a {
    grid-column: 1 / -1;
  }

  [data-theme="dark"] .site-ui .home-nav-actions.is-open {
    background: #20252a;
  }
}

/*
 * 通用控件表面状态
 * =================
 * 给控件增加下面三个 class 之一，就能指定它的默认层级：
 *   control-flat   平：标题栏命令、未选中的切换项。
 *   control-raised 凸：普通操作按钮，表示可以按下。
 *   control-inset  凹：输入区域、按下或已经选中的项目。
 *
 * 这里使用 --surface-* 变量，不写死阴影颜色。文件开头已经分别为亮色和
 * 暗色主题定义变量，所以切换主题时，同一个 class 会自动适配。
 */

/* 平：透明背景且没有阴影，与所在标题栏或面板处于同一平面。 */
.site-ui .control-flat {
  border-color: transparent;
  background: transparent;
  box-shadow: none;
  transform: none;
}

/* 凸：使用向外的短阴影，适合“点击后执行操作”的普通按钮。 */
.site-ui .control-raised {
  border-color: transparent;
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
  transform: none;
}

/* 凹：使用内阴影，适合输入框、按下状态和已经选中的项目。 */
.site-ui .control-inset {
  border-color: transparent;
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
  transform: none;
}

/* 暗色主题使用玻璃变量，而不是亮色主题的实体背景。 */
[data-theme="dark"] .site-ui .control-raised {
  border-color: var(--surface-border);
  background: var(--surface-raised);
}

[data-theme="dark"] .site-ui .control-inset {
  border-color: var(--surface-border-soft);
  background: var(--glass-well);
}

/*
 * 显式状态 class 的 hover 和按下反馈。状态 class 写在普通按钮 class 后面
 * 也没关系，因为这些规则位于文件末尾，会覆盖前面较早的按钮外观。
 */
.site-ui :is(button:not(:disabled), .btn-link).control-flat:hover {
  background: var(--surface-hover);
  box-shadow: none;
}

.site-ui :is(button:not(:disabled), .btn-link).control-raised:hover {
  background: var(--surface-hover);
  box-shadow: var(--surface-shadow-hover);
  transform: translateY(-1px);
}

.site-ui :is(button:not(:disabled), .btn-link).control-inset:hover {
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-deep);
}

.site-ui :is(button:not(:disabled), .btn-link).control-flat:active,
.site-ui :is(button:not(:disabled), .btn-link).control-raised:active {
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-pressed);
  transform: none;
}

/*
 * 标题栏按钮：默认 flat
 * =====================
 * :is(...) 把四种标题栏合并写在一条规则里。这里只选择标题栏内的按钮，
 * 不会改变页面正文里的主要或次要按钮。:not(...) 表示“没有显式指定凸或
 * 凹”；所以标题栏默认是平的，但仍可加 control-raised/control-inset 改写。
 */
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button, .btn-link):not(.control-raised):not(.control-inset) {
  border-color: transparent;
  background: transparent;
  box-shadow: none;
  transform: none;
}

/* hover 只增加轻微底色，不增加外阴影，所以仍然是 flat。 */
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button:not(:disabled), .btn-link):not(.control-raised):not(.control-inset):hover {
  border-color: transparent;
  background: var(--surface-hover);
  box-shadow: none;
  color: var(--text);
  transform: none;
}

/*
 * :active 是手指或鼠标正在按住；.is-open 和 aria-expanded=true 表示菜单
 * 已展开。这些短暂状态使用内阴影，松开或关闭后会自动恢复 flat。
 */
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button:not(:disabled), .btn-link):active,
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button, .btn-link).is-open,
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button, .btn-link)[aria-expanded="true"] {
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-inset-small);
  transform: none;
}

/* 键盘焦点是位置提示，不是凸起状态，因此只画清晰焦点环。 */
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button, .btn-link):not(.control-raised):not(.control-inset):focus-visible {
  outline: 2px solid var(--focus-inner);
  outline-offset: 2px;
  box-shadow: 0 0 0 4px var(--accent);
}

/* 显式状态在键盘聚焦时保留原来的层级，并在外侧增加焦点环。 */
.site-ui :is(button, .btn-link).control-raised:focus-visible {
  outline: 2px solid var(--focus-inner);
  outline-offset: 2px;
  box-shadow: var(--surface-shadow-small), 0 0 0 4px var(--accent);
}

.site-ui :is(button, .btn-link).control-inset:focus-visible {
  outline: 2px solid var(--focus-inner);
  outline-offset: 2px;
  box-shadow: var(--surface-shadow-deep), 0 0 0 4px var(--accent);
}

/*
 * 首页科目选择保持原来的 raised / inset 交互
 * ==========================================
 * 默认凸起、鼠标悬停时加强外阴影、按住时使用内阴影。这里不再把科目卡
 * 改成 flat，因此文件前面原有的 course-card 规则重新成为最终外观。
 */
/*
 * 试卷与做题模式选择
 * ==================
 * paper-set-item 只展示资料，真正操作在行内按钮上，所以整行保持 flat，
 * 避免让用户误以为整行都可以点击。
 */
.site-ui .paper-set-item,
[data-theme="dark"] .site-ui .paper-set-item {
  border: 0;
  border-top: 1px solid var(--surface-border-soft);
  border-radius: 0;
  background: transparent;
  box-shadow: none;
  transform: none;
}

/* 模式卡：未选中为 flat，hover 为凸，带 .selected 的当前项为凹。 */
.site-ui .mode-option-card,
[data-theme="dark"] .site-ui .mode-option-card {
  border-color: transparent;
  background: transparent;
  box-shadow: none;
  transform: none;
}

.site-ui .mode-option-card:not(.selected):hover {
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
}

[data-theme="dark"] .site-ui .mode-option-card:not(.selected):hover {
  border-color: var(--surface-border);
}

.site-ui .mode-option-card.selected {
  border-color: var(--accent);
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
}

[data-theme="dark"] .site-ui .mode-option-card.selected {
  background: var(--glass-well);
}

/* 隐藏的 radio 获得键盘焦点时，在整张模式卡外画出轮廓。 */
.site-ui .mode-option-card:focus-within {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* 旧基础样式写死了浅色文字；改用变量后，暗色主题也能正确显示。 */
.site-ui .paper-picker-head h1,
.site-ui .mode-choice-title,
.site-ui .mode-option-copy strong,
.site-ui .paper-set-title {
  color: var(--text);
}

.site-ui .mode-option-copy small,
.site-ui .paper-set-meta,
.site-ui .paper-filter-count {
  color: var(--muted);
}

/* 筛选栏本身为 flat；里面真正可以输入的 select 仍然显示为凹。 */
.site-ui .paper-filter-bar,
[data-theme="dark"] .site-ui .paper-filter-bar {
  border-color: var(--surface-border-soft);
  background: transparent;
  box-shadow: none;
}

/*
 * Biology 章节模式选择
 * ===================
 * 外层只是分组容器。里面两个按钮与模式卡相同：未选 flat、hover raised、
 * 带 .is-active 的当前模式 inset。
 */
.site-ui .chapter-mode-switch {
  border-color: var(--surface-border-soft);
  background: transparent;
  box-shadow: none;
}

.site-ui .chapter-mode-switch button {
  border-color: transparent;
  background: transparent;
  box-shadow: none;
  color: var(--muted);
  transform: none;
}

.site-ui .chapter-mode-switch button:not(.is-active):hover {
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
  color: var(--text);
}

[data-theme="dark"] .site-ui .chapter-mode-switch button:not(.is-active):hover {
  border-color: var(--surface-border);
}

.site-ui .chapter-mode-switch button.is-active {
  border-color: var(--accent);
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
  color: var(--accent);
}

[data-theme="dark"] .site-ui .chapter-mode-switch button.is-active {
  background: var(--glass-well);
}

/* 章节卡是信息分组；内部保持平整，避免“卡片里面再套卡片”。 */
.site-ui .chapter-band__heading,
.site-ui .chapter-section-row {
  background: transparent;
  color: var(--text);
}

.site-ui .chapter-band__heading {
  border-bottom: 1px solid var(--surface-border-soft);
}

.site-ui .chapter-section-row {
  border-bottom-color: var(--surface-border-soft);
}

.site-ui .chapter-band__heading p,
.site-ui .chapter-section-main span,
.site-ui .chapter-metrics dt {
  color: var(--muted);
}

.site-ui .chapter-metrics div {
  border-left-color: var(--surface-border-soft);
}

.site-ui .chapter-metrics dd {
  color: var(--text);
}

/* 章节编号是信息标签而不是按钮，使用强调色，但不添加立体阴影。 */
.site-ui .chapter-number {
  background: var(--accent);
  box-shadow: none;
  color: var(--primary-text);
}

/*
 * 文本框、下拉框和多行文本框
 * ==========================
 * 默认凹槽已经在本文件前面的表单规则中定义。这里补充键盘焦点态：保留
 * 内阴影，再加焦点环。人工指定 control-flat 或 control-raised 时不套用。
 */
.site-ui :is(
  input:not([type="radio"]):not([type="checkbox"]):not([type="range"]):not([type="file"]),
  select,
  textarea,
  .rich-text-editor
):not(.control-flat):not(.control-raised):focus-visible {
  outline: 2px solid var(--focus-inner);
  outline-offset: 2px;
  box-shadow: var(--surface-shadow-deep), 0 0 0 4px var(--accent);
}

/*
 * 文本框也可以人工改成平或凸
 * --------------------------
 * 前面旧的 input:hover/input:focus 规则会默认维持“凹槽”。这里位于文件末尾，
 * 因此当你明确写了 control-flat 或 control-raised 时，人工状态拥有优先级。
 */
.site-ui :is(input, select, textarea).control-flat:hover {
  background: transparent;
  box-shadow: none;
}

.site-ui :is(input, select, textarea).control-raised:hover {
  background: var(--surface-hover);
  box-shadow: var(--surface-shadow-hover);
}

.site-ui :is(input, select, textarea).control-flat:focus-visible {
  outline: 2px solid var(--focus-inner);
  outline-offset: 2px;
  box-shadow: 0 0 0 4px var(--accent);
}

.site-ui :is(input, select, textarea).control-raised:focus-visible {
  outline: 2px solid var(--focus-inner);
  outline-offset: 2px;
  box-shadow: var(--surface-shadow-small), 0 0 0 4px var(--accent);
}

/*
 * disabled 是“不能操作”，不是 flat/raised/inset 中的任一种。无论原来使用
 * 哪个视觉 class，禁用后都取消阴影并降低透明度，而且 hover 不会恢复阴影。
 */
.site-ui :is(button, input, select, textarea):disabled,
.site-ui :is(button, input, select, textarea):disabled:hover {
  cursor: not-allowed;
  box-shadow: none;
  opacity: 0.45;
  transform: none;
}

/*
 * 其他学生页面单向复用首页标题栏结构
 * ======================================
 * 首页保持原有规则不动；这里只让其他三种标题栏复用首页内部三列的位置：
 * 品牌在左、页面标题或导航在中、命令按钮在右。普通页面只有品牌和按钮时，
 * 右侧按钮直接放到第三列，中间列留作弹性空间，因此位置与首页完全一致。
 */
.site-ui :is(
  .site-topbar__inner,
  .chapter-topbar__inner,
  .community-topbar__inner
) {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
}

.site-ui :is(.site-header-controls, .community-topbar__actions) {
  grid-column: 3;
  justify-self: end;
}

.site-ui .community-topbar__title {
  grid-column: 2;
}

/*
 * 章节练习的作答框使用 inset
 * ==========================
 * 每个 .option-item 都是一个答案输入区域。内阴影表示内容在这里被选择或输入，
 * 与普通文本框的凹面语义一致；选对、选错的边框颜色仍由原有规则负责。
 */
.site-ui .chapter-question .option-item,
[data-theme="dark"] .site-ui .chapter-question .option-item {
  border-color: var(--surface-border-soft);
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
}

[data-theme="dark"] .site-ui .chapter-question .option-item {
  background: var(--glass-well);
}

/*
 * 真题做题页
 * ==========
 * 只在 generate.html 的 .practice-page 下生效，不影响错题本、复习页或社区。
 * 外层结果区保持平整，题目是主要 raised 表面，答案是 inset 输入区域，题号
 * 导航则使用 flat / inset 两级状态，避免旧蓝色卡片与当前全站主题混用。
 */
.site-ui.practice-page .container {
  width: min(1180px, calc(100% - 32px));
  margin: 24px auto 48px;
  gap: 16px;
}

.site-ui.practice-page[data-paper-open="true"] #generateHero,
.site-ui.practice-page[data-paper-open="true"] #resultPanel {
  border: 0;
  background: transparent;
  box-shadow: none;
}

.site-ui.practice-page[data-paper-open="true"] #generateHero {
  padding: 8px 0 16px;
  border-bottom: 1px solid var(--surface-border-soft);
}

.site-ui.practice-page[data-paper-open="true"] #generateHero h1 {
  color: var(--text);
  font-size: 1.55rem;
  letter-spacing: 0;
}

.site-ui.practice-page[data-paper-open="true"] #resultPanel {
  margin: 0;
  padding: 0;
}

.site-ui.practice-page[data-paper-open="true"] #resultPanel > h2 {
  margin: 0 0 12px;
  color: var(--text);
  font-size: 1.05rem;
  letter-spacing: 0;
}

.site-ui.practice-page .question-body-layout {
  grid-template-columns: minmax(0, 1fr) 240px;
  gap: 18px;
}

.site-ui.practice-page .question {
  margin: 0;
  padding: 24px;
  border-color: transparent;
  border-radius: 18px;
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow);
}

[data-theme="dark"] .site-ui.practice-page .question {
  border-color: var(--surface-border);
  background: var(--surface-raised);
}

.site-ui.practice-page .question h4 {
  margin: 0;
  color: var(--text);
  font-size: 1.05rem;
  line-height: 1.6;
  letter-spacing: 0;
}

.site-ui.practice-page .question .option-item {
  min-height: 52px;
  padding: 10px 12px;
  border-color: var(--surface-border-soft);
  border-radius: 16px;
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
  color: var(--text);
  cursor: pointer;
}

[data-theme="dark"] .site-ui.practice-page .question .option-item {
  background: var(--glass-well);
}

.site-ui.practice-page .question .option-item:has(input:checked) {
  border-color: var(--accent);
  background: var(--surface-pressed);
}

.site-ui.practice-page .question-side {
  position: sticky;
  top: calc(92px + env(safe-area-inset-top));
  padding: 14px;
  border-color: var(--surface-border-soft);
  border-radius: 18px;
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
}

[data-theme="dark"] .site-ui.practice-page .question-side {
  border-color: var(--surface-border);
  background: var(--surface-raised);
}

.site-ui.practice-page .question-side-title {
  margin-bottom: 10px;
  color: var(--text);
  font-size: 0.82rem;
}

.site-ui.practice-page .jump-btn {
  aspect-ratio: 1;
  padding: 0;
  border-color: transparent;
  border-radius: 12px;
  background: transparent;
  box-shadow: none;
  color: var(--text);
}

.site-ui.practice-page .jump-btn:hover {
  background: var(--surface-hover);
  box-shadow: var(--surface-shadow-small);
}

.site-ui.practice-page .jump-btn.active {
  border-color: var(--accent);
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-inset-small);
  color: var(--accent);
}

.site-ui.practice-page .tag,
.site-ui.practice-page .text-view-box {
  border-color: var(--surface-border-soft);
  background: transparent;
  box-shadow: none;
  color: var(--muted);
}

.site-ui.practice-page #paperResult > .actions {
  align-items: center;
  padding-block: 10px;
  border-bottom: 1px solid var(--surface-border-soft);
}

/*
 * 限时测试计时器
 * ==============
 * JavaScript 会把 #timerDisplay 移到标题栏右侧。标题栏本身是 sticky，所以
 * 页面滚动时计时器不会离开标题栏。练习模式和未打开试卷时使用 hidden，
 * 本文件开头的 [hidden] 规则会确保它完全不占位置。
 */
.site-ui.practice-page #timerDisplay {
  position: static;
  inset: auto;
  z-index: auto;
  width: auto;
  min-width: 150px;
  min-height: 44px;
  margin: 0;
  padding: 8px 12px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 1px solid var(--surface-border-soft);
  border-radius: 16px;
  background: var(--bg);
  box-shadow: var(--surface-shadow-inset-small);
  color: var(--text);
  font-family: "Share Tech Mono", ui-monospace, monospace;
  font-size: 0.95rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0;
  white-space: nowrap;
  transform: none;
  animation: none;
}

[data-theme="dark"] .site-ui.practice-page #timerDisplay {
  background: var(--glass-well);
}

.site-ui.practice-page #timerDisplay:hover {
  background: var(--bg);
  box-shadow: var(--surface-shadow-inset-small);
  transform: none;
}

.site-ui.practice-page #timerDisplay::before {
  width: 7px;
  height: 7px;
  background: var(--error);
  box-shadow: none;
  animation: none;
}

@media (max-width: 767px) {
  .site-ui.practice-page .container {
    width: calc(100% - 20px);
    margin-top: 14px;
  }

  .site-ui.practice-page .question-body-layout {
    grid-template-columns: 1fr;
  }

  .site-ui.practice-page .question {
    padding: 16px 14px;
  }

  .site-ui.practice-page .question-side {
    position: static;
  }

  .site-ui.practice-page #timerDisplay {
    position: static;
    min-width: 116px;
    min-height: 40px;
    padding: 6px 8px;
    font-size: 0.76rem;
  }
}

/*
 * 标题栏按钮的最终三态
 * ====================
 * 这组规则放在文件最后，统一覆盖前面的历史标题栏样式：
 *   默认：flat；hover：与“章节练习 / 真题套卷”切换按钮一样 raised；
 *   focus-visible：保留焦点轮廓，底层 raised 效果与套卷切换按钮一致；
 *   active / 菜单展开：与套卷切换按钮的当前项一样显示强调表面。
 */
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button, .btn-link):not(.control-raised):not(.control-inset) {
  border-color: transparent;
  background: transparent;
  box-shadow: none;
  transform: none;
}

.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button:not(:disabled), .btn-link):not(.control-raised):not(.control-inset):hover {
  border-color: transparent;
  background: var(--surface-raised);
  box-shadow: var(--surface-shadow-small);
  color: var(--text);
  transform: none;
}

[data-theme="dark"] .site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button:not(:disabled), .btn-link):not(.control-raised):not(.control-inset):hover {
  border-color: var(--surface-border);
}

.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button, .btn-link):not(.control-raised):not(.control-inset):focus-visible {
  border-color: transparent;
  background: var(--surface-raised);
  outline: 2px solid var(--focus-inner);
  outline-offset: 2px;
  box-shadow: var(--surface-shadow-small), 0 0 0 4px var(--accent);
  transform: translateY(-1px);
}

/* 按下和展开写在焦点之后，保证它与套卷切换按钮的当前项一致。 */
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button:not(:disabled), .btn-link):active,
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button, .btn-link).is-open,
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button, .btn-link)[aria-expanded="true"] {
  border-color: var(--accent);
  background: var(--bg);
  box-shadow: var(--surface-shadow-deep);
  color: var(--accent);
  transform: none;
}
[data-theme="dark"] .site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button:not(:disabled), .btn-link):active,
[data-theme="dark"] .site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button, .btn-link).is-open,
[data-theme="dark"] .site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button, .btn-link)[aria-expanded="true"] {
  background: var(--glass-well);
}


/* ===== Dark theme: review and curriculum surfaces (2026-08-03) =====
   Light fallbacks stay in styles.css per the convention noted there; the
   theming lives here. Each of these sets a fill but no text colour, so under
   the dark theme the inherited light text landed on a light fill and became
   unreadable. */

[data-theme="dark"] .site-ui .review-question-image {
  border-color: var(--surface-border-soft);
  background: var(--glass-fill);
}

[data-theme="dark"] .site-ui .review-question-answers > div {
  border-color: var(--surface-border-soft);
  background: var(--glass-fill);
}

[data-theme="dark"] .site-ui.curriculum-review-page {
  background: var(--bg);
}

[data-theme="dark"] .site-ui .review-legend-dot.is-unanswered {
  background: var(--glass-fill-strong);
}

/*
 * 浅色标题栏使用不透明表面
 * ========================
 * 只在根元素没有 data-theme="dark" 时生效。保留标题栏原有尺寸、圆角、
 * 边框和阴影，只把半透明玻璃底改成实色并关闭背景模糊。暗色标题栏不匹配
 * 这些选择器，因此其颜色、透明度和玻璃效果保持不变。
 */
html:not([data-theme="dark"]) .site-ui :is(
  .home-topbar__inner,
  .site-topbar__inner,
  .chapter-topbar__inner,
  .community-topbar__inner
) {
  background: #EEF5F0;
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

/*
 * 标题栏与模式按钮的按下状态修正
 * ==================================
 * :active 只在鼠标或触摸按住期间生效；菜单按钮展开后由 .is-open 或
 * aria-expanded="true" 保持同样的 inset 内阴影。
 */
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button:not(:disabled), .btn-link):active,
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button, .btn-link).is-open,
.site-ui :is(.home-topbar, .site-topbar, .chapter-topbar, .community-topbar)
  :is(button, .btn-link)[aria-expanded="true"] {
  border-color: transparent;
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-inset-small);
  color: var(--text);
  transform: none;
}

/* 当前章节模式只显示内凹选中态，不再绘制外围凸起高光。 */
.site-ui .chapter-mode-switch button.is-active,
[data-theme="dark"] .site-ui .chapter-mode-switch button.is-active {
  border-color: var(--accent);
  background: var(--surface-pressed);
  box-shadow: var(--surface-shadow-inset-small);
  color: var(--accent);
}

/* 只把真正的退出操作设为危险色；访客状态的登录按钮不会匹配。 */
.site-ui :is(#logoutHome, #communityLogout):is(
  [data-i18n="homeLogout"],
  [data-i18n="communityLogout"]
),
.site-ui :is(#logoutHome, #communityLogout):is(
  [data-i18n="homeLogout"],
  [data-i18n="communityLogout"]
):is(:hover, :focus-visible, :active) {
  color: var(--error);
}

/* 暗色模式下，套卷摘要的标签和值统一使用规范中的亮色正文。 */
[data-theme="dark"] .site-ui .mode-summary-row,
[data-theme="dark"] .site-ui .mode-summary-row > span,
[data-theme="dark"] .site-ui .mode-summary-label {
  color: var(--text);
}