:root {
  color-scheme: light;
  --accent: #6857e8;
  --accent-rgb: 104,87,232;
  --accent-dark: #4d3caf;
  --accent-ink: #382a86;
  --secondary: #168db5;
  --secondary-rgb: 22,141,181;
  --bg: #edf4ff;
  --text: #18213c;
  --muted: #66718f;
  --line: rgba(45,58,101,.13);
  --panel: rgba(255,255,255,.88);
  --panel-solid: #fff;
  --purple: var(--accent);
  --purple-soft: var(--accent-dark);
  --cyan: var(--secondary);
  --soft: rgba(var(--accent-rgb),.08);
  --shadow: 0 25px 70px rgba(var(--accent-rgb),.13);
}
:root[data-theme="ocean"] {
  --accent: #1267b5; --accent-rgb: 18,103,181; --accent-dark: #0b548f; --accent-ink: #124776;
  --secondary: #087a99; --secondary-rgb: 8,122,153; --bg: #edf7ff; --text: #172f46; --muted: #536d82; --line: rgba(31,87,132,.15);
}
:root[data-theme="forest"] {
  --accent: #24754a; --accent-rgb: 36,117,74; --accent-dark: #1d603d; --accent-ink: #214d36;
  --secondary: #52743b; --secondary-rgb: 82,116,59; --bg: #eff7ef; --text: #21392d; --muted: #5b7261; --line: rgba(48,93,63,.16);
}
:root[data-theme="sunset"] {
  --accent: #ae4e22; --accent-rgb: 174,78,34; --accent-dark: #913e19; --accent-ink: #73351f;
  --secondary: #a66720; --secondary-rgb: 166,103,32; --bg: #fff5e9; --text: #442f23; --muted: #7b6657; --line: rgba(132,83,44,.16);
}
body, .auth-gate {
  color: var(--text);
  background: radial-gradient(circle at 10% 5%, rgba(var(--accent-rgb),.16), transparent 31rem), radial-gradient(circle at 88% 70%, rgba(var(--secondary-rgb),.12), transparent 32rem), linear-gradient(var(--line) 1px, transparent 1px), linear-gradient(90deg,var(--line) 1px,transparent 1px),var(--bg);
  background-size: auto, auto, 32px 32px, 32px 32px, auto;
}
body::before { background-image: radial-gradient(circle,rgba(var(--accent-rgb),.22) 0 1px,transparent 1.3px),radial-gradient(circle,rgba(var(--secondary-rgb),.16) 0 1px,transparent 1.3px); }
body::after { background: none; }
::selection { background: rgba(var(--accent-rgb),.25); color: var(--text); }
.logo, .auth-logo, .primary, .auth-submit, .admin-primary { background: linear-gradient(135deg,var(--accent),var(--accent-dark)); color: #fff; box-shadow: 0 8px 24px rgba(var(--accent-rgb),.19); }
.lang-btn.active { background: var(--accent); }
.role-chip, .course-kicker, .unit-code, .how-number, .concept-label, .choice-index, .admin-kicker, .auth-link { color: var(--accent-dark); }
.stat-chip, .choice-index, .why-box, .auth-tab.active, .auth-language button.active { background: var(--soft); color: var(--accent-ink); }
.auth-card::before, .auth-loading-card::before, .progress-bar { background: linear-gradient(90deg,var(--accent),var(--secondary)); }
.auth-card::after { color: rgba(var(--accent-rgb),.06); }
.auth-gate::before { border-color: var(--line); box-shadow: 0 0 0 70px rgba(var(--accent-rgb),.02),0 0 0 140px rgba(var(--secondary-rgb),.015); }
.auth-gate::after { color: rgba(var(--accent-rgb),.08); }
.auth-spinner { border-top-color: var(--accent); }
.auth-tabs, .auth-language, .sidebar { background: linear-gradient(150deg,#fff,var(--bg)); }
.auth-heading, .field input, .field select, .field textarea, .admin-shell, .account-email, .side-title, .unit-title, .topic-button strong, .choice, .route-node, .compact-select, .lesson-video { color: var(--text); }
.auth-subtitle, .field-help, .auth-open-note, .admin-head p, .admin-section-copy, .data-meta, .data-description, .empty-state, .loading-line, .lesson-video p, .unit-summary, .how-card p, .mastery ul, .side-note, .count, footer, .course-note, .upload-progress, .file-drop span { color: var(--muted); }
.field label { color: var(--text); }
.auth-loading-card, .auth-card, .admin-shell, .workspace { background: var(--panel); border-color: var(--line); box-shadow: var(--shadow); }
.field input:focus, .field select:focus, .field textarea:focus, #query:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--soft); }
.subject.active { color: var(--accent-ink); background: linear-gradient(90deg,rgba(var(--accent-rgb),.16),var(--soft)); border-color: rgba(var(--accent-rgb),.28); }
.subject:hover, .choice:hover, .unit-card:hover, .example:hover, .secondary:hover, .back-control:hover { color: var(--accent-ink); background: var(--soft); }
.topic-number, .orbit-formula.one { color: var(--secondary); }
.topic-number { background: rgba(var(--secondary-rgb),.09); }
.course-head, .admin-head { background: linear-gradient(145deg,var(--soft),rgba(var(--secondary-rgb),.08)); }
.course-note { background: rgba(var(--secondary-rgb),.06); }
.question-card, .concept-card, .unit-card, .topic-button, .how-card, .data-card { background: linear-gradient(145deg,#fff,var(--bg)); border-color: var(--line); }
.unit-card::after, .concept-orbit::before { border-color: rgba(var(--accent-rgb),.22); }
.concept-orbit::after { border-color: rgba(var(--secondary-rgb),.22); }
.concept-orbit { background: radial-gradient(circle at center,rgba(var(--accent-rgb),.12),transparent 45%),linear-gradient(145deg,#fff,var(--bg)); }
.orbit-formula, .orbit-formula.four { color: var(--accent-dark); opacity: .6; }
.main-panel { background: radial-gradient(circle at 92% 8%,rgba(var(--secondary-rgb),.08),transparent 18rem); }
.why-box { color: var(--text); }
.admin-open { color: var(--accent-dark); border-color: rgba(var(--accent-rgb),.25); background: var(--soft); }
.admin-open:hover, .logout-button:hover, .admin-close:hover { color: var(--accent-ink); background: var(--soft); }
.admin-tab.active { color: var(--accent-dark); border-bottom-color: var(--accent); }
.file-drop { background: radial-gradient(circle at 50% 0,var(--soft),transparent 75%),var(--soft); border-color: rgba(var(--accent-rgb),.25); }
.account-nav-button { padding: 9px 13px; border: 1px solid var(--line); border-radius: 10px; background: rgba(255,255,255,.8); color: var(--text); font-size: .8rem; font-weight: 650; cursor: pointer; }
.account-nav-button:hover, .account-nav-button[aria-current="page"], .account-nav-button[aria-pressed="true"] { color: var(--accent-dark); border-color: var(--accent); background: var(--soft); }
button:disabled { cursor: wait; opacity: .6; }
button:focus-visible, a:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }
.user-dashboard { padding: 36px 0 54px; }
.user-shell { display: grid; grid-template-columns: 220px minmax(0,1fr); border: 1px solid var(--line); border-radius: 24px; overflow: hidden; background: var(--panel); box-shadow: var(--shadow); min-height: 620px; }
.user-sidebar { background: linear-gradient(160deg,#fff,var(--bg)); padding: 27px 18px; border-right: 1px solid var(--line); display: flex; flex-direction: column; gap: 28px; }
.user-sidebar-label { padding: 0 12px; font-size: .75rem; color: var(--muted); text-transform: uppercase; letter-spacing: .15em; font-weight: 700; }
.user-sidebar nav { display: grid; gap: 8px; }
.user-tab, .user-back { border: 0; background: transparent; border-radius: 12px; padding: 13px; text-align: left; color: var(--muted); cursor: pointer; font-size: .88rem; font-weight: 650; }
.user-tab { display: flex; align-items: center; gap: 10px; }
.user-tab span { font-size: 1.25rem; line-height: 1; }
.user-tab.active { color: var(--accent-dark); background: var(--soft); }
.user-tab:hover, .user-back:hover { background: var(--soft); color: var(--accent-dark); }
.user-back { margin-top: auto; line-height: 1.5; font-size: .8rem; }
.user-content { padding: 34px 36px 38px; min-width: 0; }
.user-kicker { color: var(--accent-dark); font-size: .73rem; font-weight: 750; letter-spacing: .1em; text-transform: uppercase; margin-bottom: 8px; }
.user-page-head h1 { margin: 0; font-size: clamp(1.8rem,4vw,2.3rem); letter-spacing: -.035em; }
.user-page-head p { color: var(--muted); font-size: .92rem; line-height: 1.7; margin: 9px 0 27px; }
.profile-banner { display: flex; align-items: center; gap: 17px; padding: 22px; background: linear-gradient(135deg,var(--soft),rgba(var(--secondary-rgb),.06)); border-radius: 16px; border: 1px solid var(--line); }
.profile-avatar { width: 66px; height: 66px; flex: 0 0 66px; border-radius: 19px; display: grid; place-items: center; background: var(--accent); color: #fff; font-size: 1.9rem; font-weight: 750; }
.profile-banner h2 { font-size: 1.25rem; margin: 0 0 5px; overflow-wrap: anywhere; }
.profile-role { color: var(--accent-dark); font-size: .83rem; }
.profile-details { display: grid; grid-template-columns: 1fr 1fr; gap: 20px 28px; margin: 27px 0; }
.profile-details dt { color: var(--muted); font-size: .78rem; margin-bottom: 7px; }
.profile-details dd { margin: 0; font-size: .95rem; font-weight: 600; overflow-wrap: anywhere; }
.role-explainer { font-size: .87rem; color: var(--muted); line-height: 1.6; }
.user-actions { display: flex; gap: 10px; flex-wrap: wrap; margin: 20px 0 27px; }
.settings-section { margin-top: 27px; padding-top: 25px; border-top: 1px solid var(--line); }
.settings-section.first { border-top: 0; padding-top: 0; margin-top: 0; }
.settings-section h2 { font-size: 1.05rem; margin: 0 0 8px; }
.settings-section > p { color: var(--muted); font-size: .85rem; line-height: 1.7; margin: 0 0 19px; }
.theme-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 15px; }
.theme-card { min-width: 0; padding: 0; border: 2px solid var(--line); border-radius: 16px; overflow: hidden; text-align: left; background: #fff; color: var(--text); cursor: pointer; transition: border-color .18s ease,box-shadow .18s ease; }
.theme-card:hover { border-color: rgba(var(--accent-rgb),.5); }
.theme-card.selected { border-color: var(--accent); box-shadow: 0 0 0 3px var(--soft); }
.theme-preview { height: 115px; padding: 16px 24px; background: var(--preview-bg); display: flex; gap: 10px; }
.preview-rail { width: 32%; padding: 13px 9px; border-radius: 8px; background: color-mix(in srgb,var(--preview-soft) 25%,white); display: grid; align-content: start; gap: 8px; }
.preview-rail i { height: 5px; border-radius: 4px; width: 85%; background: var(--preview-accent); opacity: .6; }
.preview-rail i:nth-child(2) { width: 65%; opacity: .25; }
.preview-rail i:nth-child(3) { width: 75%; opacity: .25; }
.preview-sheet { background: #fff; border-radius: 8px; flex: 1; padding: 13px 12px; display: grid; gap: 6px; align-content: start; box-shadow: 0 4px 12px #00000008; }
.preview-sheet span { height: 7px; width: 62%; background: var(--preview-accent); border-radius: 4px; }
.preview-sheet i { height: 4px; width: 90%; background: var(--preview-soft); border-radius: 4px; opacity: .6; }
.preview-sheet i:nth-child(3) { width: 70%; }
.preview-sheet b { width: 34%; height: 10px; border-radius: 4px; margin-top: 5px; background: var(--preview-accent); }
.theme-card-copy { padding: 16px; display: grid; gap: 7px; }
.theme-card-copy > strong { font-size: .92rem; }
.theme-card-copy > span { color: var(--muted); font-size: .77rem; line-height: 1.5; }
.theme-card-bottom { display: flex; gap: 8px; align-items: center; justify-content: space-between; margin-top: 5px; }
.theme-swatches { display: flex; gap: 4px; }
.theme-swatches i { width: 14px; height: 14px; border-radius: 50%; border: 1px solid #0000000d; }
.theme-state { color: var(--muted); font-size: .73rem; }
.theme-card.selected .theme-state { color: var(--accent-dark); font-weight: 750; }
.settings-language { display: flex; gap: 9px; }
.settings-section > .preferences-notice { margin-top: 16px; margin-bottom: 0; font-size: .77rem; }
@media (max-width: 920px) { .header-actions { max-width: 85%; } .user-shell { grid-template-columns: 180px minmax(0,1fr); } .user-content { padding: 28px 24px; } }
@media (max-width: 680px) {
  header { flex-wrap: wrap; gap: 12px; }
  .header-actions { max-width: 100%; flex: 1; }
  .account-zone { flex-wrap: wrap; }
  .account-nav-button { padding: 8px 10px; font-size: .76rem; }
  .user-dashboard { padding-top: 22px; }
  .user-shell { grid-template-columns: 1fr; min-height: auto; }
  .user-sidebar { padding: 13px 15px; border-right: 0; border-bottom: 1px solid var(--line); gap: 12px; }
  .user-sidebar-label { display: none; }
  .user-sidebar nav { grid-template-columns: 1fr 1fr; }
  .user-back { margin-top: 0; padding: 4px 12px; }
  .user-content { padding: 24px 19px 28px; }
  .profile-details { gap: 20px; }
  .theme-preview { padding: 13px; }
  .theme-card-copy { padding: 13px; }
}
@media (max-width: 380px) { .theme-grid, .profile-details { grid-template-columns: 1fr; } .brand > span { display: none; } }