/* Educator workspace: Bootstrap foundation, shared semantic color tokens.
   Shape scale: controls 8px, panels 16px, small badges 6px.
   Layers: skip link 2; Bootstrap toast 1090. Motion marks appearance changes. */
@font-face {
  font-family: Geist;
  src: url('/assets/fonts/geist-variable.woff2') format('woff2');
  font-style: normal;
  font-weight: 100 900;
  font-display: swap;
}
:root {
  color-scheme: light;
  --app-primary: #253d81;
  --app-primary-dark: #1c306b;
  --accent: #253d81;
  --accent-hover: #1c306b;
  --accent-soft: #edf1fb;
  --accent-text: #f9faff;
  --app-bg: #f6f7fa;
  --surface: #fefeff;
  --surface-subtle: #f8f9fc;
  --border: #dfe3ec;
  --border-hover: #7c899e;
  --text: #202a3d;
  --muted: #5c687c;
  --danger: #ac233c;
  --danger-soft: #fff0f2;
  --focus-ring: #5374c6;
  --shadow-sm: 0 2px 4px rgb(35 51 81 / 3%), 0 12px 36px rgb(35 51 81 / 4%);
  --appearance-transition: background-color 320ms ease, color 320ms ease, border-color 320ms ease, box-shadow 320ms ease;
  --app-font-family: Geist, system-ui, -apple-system, 'Segoe UI', sans-serif;
  --bs-body-font-family: var(--app-font-family);
  --bs-body-color: var(--text);
  --bs-body-bg: var(--app-bg);
  --bs-secondary-color: var(--muted);
  --bs-link-color: var(--accent);
  --bs-link-hover-color: var(--accent-hover);
  --bs-border-color: var(--border);
}
:root[data-bs-theme='dark'] {
  color-scheme: dark;
  --app-primary: #afc2fa;
  --app-primary-dark: #cad7fb;
  --accent: #afc2fa;
  --accent-hover: #cad7fb;
  --accent-soft: #23314f;
  --accent-text: #17243f;
  --app-bg: #121722;
  --surface: #1a2130;
  --surface-subtle: #1e2738;
  --border: #333f54;
  --border-hover: #79879f;
  --text: #f1f3fa;
  --muted: #b0bdd2;
  --danger: #ffa0b0;
  --danger-soft: #3a2632;
  --focus-ring: #b1c6ff;
  --shadow-sm: 0 2px 4px rgb(9 15 29 / 12%), 0 12px 36px rgb(9 15 29 / 16%);
  --bs-tertiary-bg: var(--surface-subtle);
}
* { box-sizing: border-box; }
/* Animate only painted theme colors; layout and the toggle's spring stay independent. */
:where(body, a, .app-header, .brand-mark, .header-divider, .workspace-intro > p,
  .text-secondary, .text-muted, .upload-area, .upload-icon, .upload-choose, .upload-hint,
  .document-bar, .document-icon, .document-detail, .copied-count, .results-empty,
  .results-loading, .empty-icon, .empty-content p, .format-control, .format-control label,
  .result-summary, .form-label, .equation-list, .equation-item, .equation-card,
  .equation-number, .page-link, .page-ellipsis, .page-position, .alert,
  .skeleton-row, .skeleton-row span, .processing-lines span, .toast-body > .icon,
  .login-card, .login-lock, .noscript-notice, .is-typesetting .equation-content::after) {
  transition: var(--appearance-transition);
}
body { width: 100%; max-width: none; min-height: 100dvh; margin: 0; color: var(--text); background: var(--app-bg); font-family: var(--app-font-family); font-size: 0.9375rem; line-height: 1.6; }
[v-cloak], [hidden] { display: none !important; }
h1, h2, h3, p { margin: 0; }
a { color: var(--accent); }
.icon { width: 1.25rem; height: 1.25rem; flex: 0 0 auto; vertical-align: middle; }
.text-secondary, .text-muted { color: var(--muted) !important; }
.file-name { display: block; min-width: 0; overflow-wrap: anywhere; }
.app-header { height: 76px; background: var(--surface); border-bottom: 1px solid var(--border); }
.header-inner { width: min(100% - 4rem, 1200px); height: 100%; margin-inline: auto; display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.app-brand, .header-actions { display: flex; align-items: center; gap: 0.75rem; }
.brand-name { font-size: 1.0625rem; font-weight: 650; letter-spacing: -0.035em; white-space: nowrap; }
.brand-mark { display: grid; place-items: center; width: 36px; height: 40px; border-radius: 8px; color: var(--accent); background: var(--accent-soft); }
.brand-mark .icon { width: 23px; height: 23px; }
.header-divider { width: 1px; height: 24px; background: var(--border); margin-inline: 0.125rem; }
.btn { --bs-btn-border-radius: 8px; min-height: 44px; padding: 0.625rem 1rem; font-size: 0.875rem; font-weight: 550; display: inline-flex; align-items: center; justify-content: center; gap: 0.5rem; white-space: nowrap; transition: transform 150ms ease, var(--appearance-transition); }
.btn:active:not(:disabled) { transform: translateY(1px); }
.btn-primary { --bs-btn-bg: var(--app-primary); --bs-btn-border-color: var(--app-primary); --bs-btn-hover-bg: var(--app-primary-dark); --bs-btn-hover-border-color: var(--app-primary-dark); --bs-btn-active-bg: var(--app-primary-dark); --bs-btn-active-border-color: var(--app-primary-dark); --bs-btn-color: var(--accent-text); --bs-btn-hover-color: var(--accent-text); --bs-btn-active-color: var(--accent-text); --bs-btn-disabled-bg: var(--app-primary); --bs-btn-disabled-border-color: var(--app-primary); --bs-btn-disabled-color: var(--accent-text); }
.btn.appearance-toggle {
  --toggle-color: #9a5700;
  --toggle-sky: #fff0cb;
  --toggle-spring: cubic-bezier(0.22, 1.5, 0.36, 1);
  display: grid;
  place-items: center;
  gap: 0;
  width: 44px;
  height: 44px;
  padding: 0;
  color: var(--toggle-color);
  background: transparent;
  border: 1px solid transparent;
  border-radius: 50%;
  transition: transform 220ms var(--toggle-spring), color 200ms ease;
}
.appearance-toggle::before, .appearance-toggle::after, .appearance-toggle .icon {
  grid-area: 1 / 1;
  pointer-events: none;
}
.appearance-toggle::before {
  content: '';
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--toggle-sky);
  transition: background-color 240ms ease, transform 400ms var(--toggle-spring);
}
.appearance-toggle .icon {
  position: relative;
  width: 22px;
  height: 22px;
  transform-origin: center;
  transition: transform 620ms var(--toggle-spring), opacity 180ms ease;
}
.appearance-sun { opacity: 1; transform: rotate(0) scale(1); }
.appearance-moon { opacity: 0; transform: rotate(-100deg) scale(0.2); }
.appearance-toggle::after {
  content: '';
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: currentColor;
  box-shadow: 5px 6px 0 -0.5px currentColor;
  opacity: 0;
  transform: translate(7px, -8px) scale(0);
  transition: transform 500ms var(--toggle-spring), opacity 180ms ease;
}
:root[data-bs-theme='dark'] .appearance-toggle { --toggle-color: #c6d4ff; --toggle-sky: #2a395b; }
:root[data-bs-theme='dark'] .appearance-sun { opacity: 0; transform: rotate(100deg) scale(0.2); }
:root[data-bs-theme='dark'] .appearance-moon { opacity: 1; transform: rotate(0) scale(1); }
:root[data-bs-theme='dark'] .appearance-toggle::after { opacity: 1; transform: translate(7px, -8px) scale(1); transition-delay: 120ms; }
@media (hover: hover) and (prefers-reduced-motion: no-preference) {
  .appearance-toggle:hover::before { transform: scale(1.1); }
  .appearance-toggle:hover .appearance-sun { transform: rotate(25deg) scale(1.08); }
  :root[data-bs-theme='dark'] .appearance-toggle:hover .appearance-sun { transform: rotate(100deg) scale(0.2); }
  :root[data-bs-theme='dark'] .appearance-toggle:hover .appearance-moon { transform: rotate(-12deg) scale(1.08); }
}
@media (prefers-reduced-motion: no-preference) {
  .btn.appearance-toggle:active { transform: scale(0.88); }
}
.sign-out-btn:hover, .password-toggle:hover { color: var(--accent); background: var(--accent-soft); }
.sign-out-btn { color: var(--muted); padding-inline: 0.5rem; }
:where(button, a, input, select, summary, [tabindex]):focus-visible { outline: 3px solid var(--focus-ring) !important; outline-offset: 4px; box-shadow: none !important; }
:where(main, h1, h2)[tabindex='-1']:focus { outline: none !important; }
.skip-link { position: fixed; z-index: 2; top: 1rem; left: 1rem; padding: 0.75rem 1rem; color: var(--accent); background: var(--surface); border-radius: 8px; transform: translateY(-200%); }
.skip-link:focus { transform: translateY(0); }
.workspace { width: min(100% - 4rem, 680px); margin-inline: auto; padding: 3.5rem 0; }
.workspace.has-document { width: min(100% - 4rem, 960px); padding-top: 2.5rem; }
.workspace-intro { margin-bottom: 1.75rem; }
.workspace-intro h1 { font-size: 1.875rem; line-height: 1.2; font-weight: 600; letter-spacing: -0.045em; margin-bottom: 0.75rem; }
.workspace-intro > p { color: var(--muted); font-size: 0.9375rem; }
.upload-panel { margin-bottom: 1.5rem; }
h2 { font-size: 1.125rem; font-weight: 600; letter-spacing: -0.025em; line-height: 1.4; }
.upload-area { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 0.5rem; width: 100%; min-height: 288px; margin: 0; padding: 1.5rem 1rem; color: var(--text); background: var(--surface); border: 1px dashed var(--border-hover); border-radius: 16px; font: inherit; cursor: pointer; }
.upload-area:hover:not(:disabled), .upload-area.dragover { border-color: var(--accent); background: var(--accent-soft); }
.upload-area:disabled { cursor: default; }
.upload-area:disabled:not(.is-processing) { opacity: 0.55; }
.upload-icon { width: 48px; height: 48px; display: grid; place-items: center; margin-bottom: 0.5rem; color: var(--accent); background: var(--surface); border: 1px solid var(--border); border-radius: 12px; }
.upload-icon .icon { width: 24px; height: 24px; }
.upload-label { max-width: 100%; font-weight: 550; font-size: 0.9375rem; line-height: 1.5; }
.upload-choose { display: inline-flex; align-items: center; gap: 0.625rem; margin-top: 0.75rem; border-radius: 8px; background: var(--app-primary); color: var(--accent-text); padding: 0.625rem 0.875rem; font-size: 0.8125rem; font-weight: 550; white-space: nowrap; }
.file-input { display: none; }
.document-detail { display: block; color: var(--muted); font-size: 0.75rem; margin-top: 0.25rem; }
.results-section { min-width: 0; scroll-margin-top: 1.5rem; }
@media (prefers-reduced-motion: no-preference) {
  .results-ready { animation: results-arrive 360ms cubic-bezier(0.22, 1, 0.36, 1) backwards; }
}
@keyframes results-arrive {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}
.results-heading { display: flex; align-items: center; justify-content: space-between; gap: 1rem; margin-bottom: 1.25rem; }
.results-heading h1 { font-size: 1.5rem; font-weight: 550; letter-spacing: -0.035em; line-height: 1.4; }
.copied-count { font-size: 0.75rem; color: var(--muted); white-space: nowrap; font-variant-numeric: tabular-nums; }
.results-empty, .results-loading { background: var(--surface); border: 1px solid var(--border); border-radius: 16px; overflow: hidden; }
.empty-content { display: flex; align-items: center; flex-direction: column; text-align: center; padding: 3.25rem 2rem 2.75rem; }
.empty-icon { display: grid; place-items: center; width: 52px; height: 60px; border: 1px solid var(--border); border-radius: 12px; margin-bottom: 1.25rem; background: var(--surface-subtle); color: var(--muted); }
.empty-icon .icon { width: 28px; height: 28px; }
.empty-content h2 { font-size: 1.0625rem; font-weight: 550; letter-spacing: -0.025em; margin-bottom: 0.625rem; }
.empty-content p { color: var(--muted); max-width: 41ch; font-size: 0.875rem; }
.output-toolbar { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 0.75rem; margin-bottom: 1rem; }
.format-control { position: relative; isolation: isolate; display: inline-grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0.25rem; margin: 0; padding: 4px; border: 1px solid var(--border); border-radius: 12px; background: var(--surface-subtle); min-width: 0; max-width: 100%; }
.format-control::before {
  content: '';
  position: absolute;
  z-index: 0;
  inset-block: 4px;
  left: 4px;
  width: calc((100% - 12px) / 2);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: 0 1px 4px rgb(35 51 81 / 12%);
  pointer-events: none;
  transform: translateX(0);
  transition: transform 300ms cubic-bezier(0.22, 1, 0.36, 1), var(--appearance-transition);
}
.format-control:has(#formatToggle:checked)::before { transform: translateX(calc(100% + 4px)); }
.format-control label { position: relative; z-index: 1; display: flex; justify-content: center; align-items: center; gap: 0.5rem; padding: 0.625rem 0.875rem; min-height: 44px; border-radius: 8px; font-size: 0.8125rem; font-weight: 550; color: var(--muted); cursor: pointer; white-space: nowrap; }
.format-control label.selected { color: var(--accent); }
.format-control input { position: absolute; opacity: 0; width: 1px; height: 1px; }
.format-control label:has(input:focus-visible) { outline: 3px solid var(--focus-ring); outline-offset: 3px; }
.format-control .icon { width: 18px; height: 18px; }
.result-summary { display: flex; align-items: center; justify-content: space-between; gap: 1rem; margin-bottom: 0.875rem; color: var(--muted); font-size: 0.75rem; }
.page-size-control { display: flex; align-items: center; gap: 0.625rem; }
.form-label { display: block; margin-bottom: 0.5rem; font-size: 0.8125rem; color: var(--text); font-weight: 550; }
.form-control, .form-select { color: var(--text); background-color: var(--surface); border: 1px solid var(--border-hover); border-radius: 8px; min-height: 44px; font-size: 0.875rem; transition: var(--appearance-transition); }
.form-control:focus, .form-select:focus { color: var(--text); background-color: var(--surface); border-color: var(--accent); box-shadow: none; }
.page-size-control .form-select { width: auto; min-width: 72px; min-height: 36px; padding-block: 0.25rem; font-size: 0.75rem; }
.equation-list { background: var(--surface); border: 1px solid var(--border); border-radius: 16px; overflow: hidden; }
.equation-item { cursor: pointer; }
.equation-item + .equation-item { border-top: 1px solid var(--border); }
.equation-card { display: grid; grid-template-columns: 24px minmax(0, 1fr) auto; gap: 1rem; align-items: center; padding: 1rem 1.25rem; min-height: 88px; }
.equation-item:hover .equation-card { background: var(--surface-subtle); }
.equation-item .equation-card.copied { background: var(--accent-soft); }
.equation-number { color: var(--muted); font-size: 0.75rem; font-variant-numeric: tabular-nums; }
.equation-content { overflow-x: auto; min-width: 0; padding: 0.75rem 0.25rem; font-size: 1.0625rem; }
.equation-content .mathjax-equation { white-space: nowrap; }
.equation-content:focus-visible { outline-offset: 0; }
.copy-btn { min-width: 108px; border: 1px solid var(--border); color: var(--accent); background: var(--surface); font-size: 0.75rem; padding-inline: 0.75rem; }
.copy-btn .icon { width: 16px; height: 16px; }
.copy-btn:hover { background: var(--accent-soft); color: var(--accent); border-color: var(--accent); }
.copy-confirmed .copy-btn { border-color: var(--accent); }
@media (prefers-reduced-motion: no-preference) {
  .copy-confirmed .copy-btn .icon { animation: copy-check-pop 320ms cubic-bezier(0.22, 1, 0.36, 1); }
}
@keyframes copy-check-pop {
  0% { opacity: 0.4; transform: scale(0.6) rotate(-15deg); }
  55% { opacity: 1; transform: scale(1.18) rotate(4deg); }
  100% { opacity: 1; transform: scale(1) rotate(0); }
}
.pagination-nav { display: flex; align-items: center; justify-content: space-between; gap: 0.5rem; margin-top: 1.5rem; }
.pagination-direction { color: var(--muted); font-size: 0.75rem; padding-inline: 0.5rem; }
.pagination-direction .icon { width: 16px; height: 16px; }
.pagination-direction:hover { color: var(--accent); background: var(--accent-soft); }
.page-numbers { display: flex; align-items: center; gap: 0.125rem; }
.page-link { display: grid; place-items: center; border: 0; min-width: 36px; height: 40px; border-radius: 8px; background: transparent; color: var(--muted); font-size: 0.75rem; transition: var(--appearance-transition); }
.page-link.active { background: var(--accent-soft); color: var(--accent); font-weight: 650; }
.page-link:hover { background: var(--surface); color: var(--accent); }
.page-ellipsis { color: var(--muted); font-size: 0.75rem; }
.page-position { display: none; color: var(--muted); font-size: 0.75rem; }
.alert { display: flex; align-items: flex-start; gap: 0.625rem; padding: 1rem; font-size: 0.8125rem; border-radius: 8px; }
.alert-danger { color: var(--danger); background: var(--danger-soft); border: 1px solid var(--danger); }
.alert .icon { margin-top: 0.1rem; }
.alert p { margin: 0; }
.alert .btn { margin-top: 0.75rem; }
.results-loading { padding: 1.5rem; }
.skeleton-row { display: flex; align-items: center; gap: 1.5rem; min-height: 88px; border-top: 1px solid var(--border); }
.skeleton-row span, .processing-lines span { display: block; background: var(--border); border-radius: 6px; }
.skeleton-number { width: 16px; height: 16px; }
.skeleton-equation { width: 40%; height: 20px; }
.skeleton-row:nth-child(3) .skeleton-equation { width: 55%; }
.skeleton-button { width: 88px; height: 36px; margin-left: auto; }
.processing-lines { display: grid; gap: 6px; width: 110px; margin-top: 1rem; }
.processing-lines span { height: 5px; }
.processing-lines span:last-child { width: 70%; }
.toast { --bs-toast-bg: var(--surface); --bs-toast-color: var(--text); --bs-toast-border-color: var(--border); width: auto; max-width: min(400px, calc(100vw - 2rem)); border-radius: 12px; box-shadow: var(--shadow-sm); transition: opacity 150ms linear, var(--appearance-transition); }
.toast-body { display: flex; align-items: center; gap: 0.75rem; padding: 0.75rem 1rem; font-size: 0.8125rem; }
.toast-body > .icon { color: var(--accent); }
.toast-close { width: 36px; min-height: 36px; padding: 0; color: var(--muted); }
.login-page { display: flex; flex-direction: column; }
.login-panel { width: min(100% - 2rem, 420px); margin: clamp(3rem, 12vh, 7rem) auto; }
.login-card { padding: 2rem; border: 1px solid var(--border); border-radius: 16px; background: var(--surface); box-shadow: var(--shadow-sm); }
.login-lock { display: grid; place-items: center; width: 40px; height: 40px; border: 1px solid var(--border); border-radius: 12px; color: var(--accent); margin-bottom: 1.375rem; }
#loginForm { margin-top: 1.75rem; }
.password-control { position: relative; margin-bottom: 1.25rem; }
.password-control .form-control { min-height: 48px; padding-right: 3rem; }
.password-toggle { position: absolute; top: 2px; right: 2px; width: 44px; padding: 0; color: var(--muted); }
#signInButton { min-height: 48px; }
.noscript-notice { margin: 1.5rem; padding: 1rem; background: var(--danger-soft); color: var(--danger); }

.upload-hint { color: var(--muted); font-size: 0.8125rem; text-align: center; margin-top: 1rem; }
.document-bar { display: flex; align-items: center; gap: 1rem; padding: 1.125rem 1.25rem; margin-bottom: 2rem; background: var(--surface); border: 1px solid var(--border); border-radius: 12px; }
.document-bar.dragover { border-color: var(--accent); background: var(--accent-soft); }
.document-icon { display: grid; place-items: center; width: 40px; height: 44px; border-radius: 8px; background: var(--accent-soft); color: var(--accent); flex: 0 0 auto; }
.document-info { flex: 1; min-width: 0; }
.document-info .file-name { font-size: 0.875rem; font-weight: 550; }
.replace-file-btn { color: var(--accent); background: var(--surface); border: 1px solid var(--border-hover); font-size: 0.8125rem; }
.replace-file-btn:hover { color: var(--accent); background: var(--accent-soft); border-color: var(--accent); }
.login-card h1 { font-size: 1.5rem; font-weight: 550; letter-spacing: -0.04em; }
.is-typesetting .equation-content { position: relative; }
.is-typesetting .mathjax-equation { opacity: 0; }
.is-typesetting .equation-content::after { content: ''; position: absolute; left: 0.25rem; top: calc(50% - 8px); width: 45%; height: 16px; border-radius: 6px; background: var(--border); }
@media (max-width: 767px) {
  .header-inner, .workspace, .workspace.has-document { width: calc(100% - 2rem); }
  .app-header { height: 68px; }
  .brand-name { font-size: 0.9375rem; }
  .app-brand { gap: 0.5rem; }
  .brand-mark { width: 30px; height: 36px; }
  .header-actions { gap: 0.25rem; }
  .header-divider, .sign-out-btn > .icon { display: none; }
  .sign-out-btn { font-size: 0.75rem; }
  .workspace, .workspace.has-document { padding-top: 2rem; }
  .workspace-intro h1 { font-size: 1.75rem; }
  .workspace-intro > p { font-size: 0.875rem; }
  .upload-area { min-height: 256px; }
  .upload-hint { font-size: 0.75rem; }
  .document-bar { display: grid; grid-template-columns: 40px minmax(0, 1fr); gap: 0.75rem; padding: 1rem; margin-bottom: 1.5rem; }
  .replace-file-btn { grid-column: 1 / -1; width: 100%; }
  .results-heading h1 { font-size: 1.375rem; }
  .empty-content { padding: 2.5rem 1.25rem 2rem; }
  .format-control label { font-size: 0.75rem; padding-inline: 0.5rem; gap: 0.375rem; }
  .format-control .icon { width: 16px; height: 16px; }
  .equation-card { grid-template-columns: 16px minmax(0, 1fr) auto; gap: 0.5rem; padding: 0.875rem 0.75rem; }
  .copy-btn { min-width: 92px; padding-inline: 0.5rem; gap: 0.375rem; font-size: 0.75rem; }
  .equation-content { font-size: 1rem; }
  .page-numbers { display: none; }
  .page-position { display: inline; }
  .login-panel { margin-block: 2.5rem; }
  .login-card { padding: 1.5rem; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; animation: none !important; scroll-behavior: auto !important; }
}