/* ============================================================
   shuxue.icu  —  MULTI-THEME DESIGN SYSTEM
   Black + White + Accent. Minimal colors. Geometric sans-serif.
   Three themes: PKU / TSINGHUA / CYAN (default: CYAN)
   ============================================================ */

/* --- Design Tokens (default: CYAN theme) --- */
:root {
  /* backgrounds (pure black depth — never change) */
  --bg-0: #000000;  --bg-1: #0a0a0a;  --bg-2: #111111;  --bg-3: #1a1a1a;
  /* text (white primary, bright gray for nav — never change) */
  --tx-1: #ffffff;  --tx-2: #d1d1d6;  --tx-3: #6e6e73;
  /* accent — CYAN default */
  --accent: #00d4ff;
  --accent-dim: rgba(0,212,255,.08);
  --accent-line: rgba(0,212,255,.25);
  --accent-hover: rgba(0,212,255,.15);
  /* semantic (minimal: red for errors, accent-light for moderate) */
  --err: #ff453a;  --warn: #0ea5e9;
  /* lines (white-based subtle borders) */
  --line: rgba(255,255,255,.08);  --line-strong: rgba(255,255,255,.15);  --line-dash: rgba(255,255,255,.06);
  /* fonts (Space Grotesk — tech aesthetic) */
  --font-display: "Space Grotesk","Inter",system-ui,sans-serif;
  --font-body: "Space Grotesk","Inter","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --font-mono: "Space Grotesk","SF Mono",Consolas,monospace;
  /* spacing scale */
  --sp-1:4px; --sp-2:8px; --sp-3:12px; --sp-4:16px; --sp-5:24px; --sp-6:32px;
  /* legacy aliases (kept for app.js compatibility) */
  --bg-primary:#000000; --bg-secondary:#0a0a0a; --bg-card:#0a0a0a;
  --bg-card-hover:#111111; --border-color:rgba(255,255,255,.08);
  --text-primary:#ffffff; --text-secondary:#d1d1d6; --text-muted:#6e6e73;
  --accent-blue:#00d4ff; --accent-green:#00d4ff; --accent-purple:#00d4ff;
  --accent-orange:#0ea5e9; --accent-red:#ff453a; --accent-yellow:#0ea5e9;
  --radius:0; --radius-sm:0; --shadow:none; --transition:color .15s,background-color .15s,border-color .15s;
}

/* --- Base Reset --- */
* { margin:0; padding:0; box-sizing:border-box; }
body {
  font-family: var(--font-body);
  background: var(--bg-0);
  color: var(--tx-1);
  min-height: 100vh;
  font-size: 14px;
  font-variant-numeric: tabular-nums;
}

/* --- Navbar (52px, hairline bottom) --- */
.navbar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 20px; height: 52px;
  background: var(--bg-1);
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 100;
}

.demo-notice {
  margin: 0;
  padding: 9px 20px;
  border-bottom: 1px solid var(--accent-line);
  background: var(--accent-dim);
  color: var(--tx-2);
  text-align: center;
  font-size: 11px;
  letter-spacing: .06em;
}
.nav-brand { display:flex; align-items:center; gap:8px; position:relative; height:100%; cursor:pointer; }
/* hover bridge — transparent zone below nav-brand so mouse can reach dropdown without losing hover */
.nav-brand::after {
  content: '';
  position: absolute;
  left: 0; right: 0;
  top: 100%;
  height: 32px;
}

/* --- Brand Dropdown Theme Picker --- */
.brand-dropdown {
  position: absolute; top: 100%; left: 0; z-index: 200;
  background: var(--bg-2); border: 1px solid var(--line-strong);
  padding: 6px 0; min-width: 180px;
  opacity: 0; visibility: hidden; transform: translateY(-4px);
  transition: opacity .2s, visibility .2s, transform .2s;
}
.nav-brand:hover .brand-dropdown {
  opacity: 1; visibility: visible; transform: translateY(0);
}
/* JS-controlled open state (primary mechanism — more reliable than CSS hover) */
.brand-dropdown.open {
  opacity: 1; visibility: visible; transform: translateY(0);
}
.brand-dropdown-item {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 16px; cursor: pointer; border: none; background: transparent;
  font-family: var(--font-body); font-size: 12px; font-weight: 500;
  letter-spacing: .06em; color: #d1d1d6;
  transition: var(--transition); width: 100%; text-align: left;
}
.brand-dropdown-item:hover { background: var(--bg-3); color: #ffffff; }
.brand-dropdown-item.active { color: #ffffff; }
.brand-dropdown-dot {
  width: 10px; height: 10px; border-radius: 0; flex-shrink: 0;
}
.brand-dropdown-item.active .brand-dropdown-check {
  display: inline;
}
.brand-dropdown-check {
  display: none; font-size: 10px; margin-left: 4px; color: var(--accent);
}
.nav-logo { display:none; } /* emoji removed */
.nav-title h1 {
  font-family: var(--font-display); font-size: 15px; font-weight: 700;
  line-height: 1; letter-spacing: .02em; color: var(--tx-1);
}
.nav-title h1 .proto { color: var(--accent); } /* the .icu */
.nav-subtitle {
  font-family: var(--font-display); font-size: 9px; font-weight: 500;
  letter-spacing: .14em; color: var(--tx-3); text-transform: uppercase;
}

/* nav tabs (4-column, no numbers) — colors independent of theme */
.nav-tabs { display:flex; gap:0; }
.nav-tab {
  display:flex; align-items:center; gap:0;
  padding: 14px 20px; border:none; background:transparent;
  cursor:pointer; position:relative;
  text-decoration:none;
  color: #d1d1d6; /* inactive: bright gray — always visible on dark bg */
  font-family: var(--font-body); font-size: 13px; font-weight: 500;
  letter-spacing: .08em;
  transition: var(--transition);
}
.nav-tab .tab-label { /* fallback for wrapped text */ }
.nav-tab:hover { background: var(--bg-2); color: #ffffff; }
.nav-tab:hover .tab-label { color: #ffffff; }
.nav-tab.active { background: var(--accent-dim); color: #ffffff; }
.nav-tab.active .tab-label { color: #ffffff; }
.nav-tab.active::after {
  content:''; position:absolute; left:0; right:0; bottom:-1px;
  height: 2px; background: var(--accent); /* accent indicator */
}
.tab-icon { display:none; } /* emoji removed */

/* user block */
.nav-user { display:flex; align-items:center; gap:8px; }
.nav-date {
  font-family: var(--font-display); font-size: 11px; color: var(--tx-3);
  letter-spacing: .05em;
}
.user-avatar {
  width: 28px; height: 28px; border-radius: 0;
  border: 1px solid var(--line-strong);
  display:flex; align-items:center; justify-content:center;
  font-family: var(--font-display); font-size: 10px; font-weight: 700;
  color: var(--tx-2); background: transparent;
}
.user-name { font-family: var(--font-body); font-size: 12px; color: var(--tx-2); }

/* --- Sub-Navigation (within merged pages) --- */
.sub-nav {
  display:flex; align-items:center; gap:0;
  border-bottom: 1px solid var(--line);
  margin-bottom: var(--sp-4);
}
.sub-nav-btn {
  padding: 10px 20px; border:none; background:transparent;
  cursor:pointer; font-family: var(--font-body);
  font-size: 13px; font-weight: 500; letter-spacing: .06em;
  color: #d1d1d6; transition: var(--transition); /* bright gray — independent of theme */
  position: relative;
}
.sub-nav-btn:hover { color: #ffffff; }
.sub-nav-btn.active {
  color: #ffffff; background: var(--accent-dim);
}
.sub-nav-btn.active::after {
  content:''; position:absolute; left:0; right:0; bottom:-1px;
  height: 2px; background: var(--accent);
}

/* --- Dashboard Overview Stats --- */
.dash-overview {
  margin-bottom: var(--sp-5);
}

/* --- Main Content --- */
.main-content { padding: 20px; max-width: 1400px; margin: 0 auto; }
.page { display: none; animation: fadeIn .1s ease; }
.page.active { display: block; }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

/* --- Section Headers (SpaceX clean style, no terminal prefix) --- */
.section-title {
  display:flex; align-items:center; gap:8px;
  font-family: var(--font-display); font-size: 16px; font-weight: 600;
  letter-spacing: .04em; color: var(--tx-1); margin-bottom: var(--sp-4);
}
.section-title .meta {
  margin-left: auto; font-family: var(--font-display);
  font-size: 10px; font-weight: 500; letter-spacing: .1em;
  color: var(--tx-3); text-transform: uppercase;
}

/* --- Stats Strip (number-first, no icons) --- */
.stats-grid {
  display: grid; grid-template-columns: repeat(4, 1fr);
  gap: 0; margin-bottom: var(--sp-5);
  border: 1px solid var(--line);
}
.stat-card {
  background: var(--bg-1); border-right: 1px solid var(--line);
  padding: 14px 16px; display:flex; flex-direction:column; gap:4px;
  position: relative; transition: var(--transition);
}
.stat-card:last-child { border-right: none; }
.stat-card::before { display:none; } /* gradient bar removed */
.stat-card:hover { background: var(--bg-2); }
.stat-icon { display:none; } /* emoji removed */
.stat-info { display:flex; flex-direction:column; gap:2px; }
.stat-label {
  font-family: var(--font-display); font-size: 9px; font-weight: 600;
  letter-spacing: .12em; color: var(--tx-3); text-transform: uppercase;
}
.stat-value {
  font-family: var(--font-display); font-size: 32px; font-weight: 700;
  line-height: 1; color: var(--accent); letter-spacing: -.02em;
}
.stat-trend {
  font-family: var(--font-display); font-size: 10px; font-weight: 600;
  letter-spacing: .06em; padding: 0; border: none; border-radius: 0;
  white-space: nowrap; background: none !important;
}
.stat-trend.up { color: var(--accent); }
.stat-trend.down { color: var(--err); }

/* --- Chart Cards --- */
.charts-row {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 0; margin-bottom: var(--sp-4);
  border: 1px solid var(--line); border-top: none;
}
.chart-card {
  background: var(--bg-1); border-right: 1px solid var(--line);
  border-top: 1px solid var(--line); padding: 16px;
  transition: var(--transition);
}
.chart-card:last-child { border-right: none; }
.chart-card:hover { background: var(--bg-2); }
.chart-card.full { grid-column: 1 / -1; margin-bottom: 0; }
.chart-header {
  display:flex; align-items:center; justify-content: space-between;
  margin-bottom: 12px; padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}
.chart-header h3 {
  font-family: var(--font-body); font-size: 13px; font-weight: 600;
  letter-spacing: .04em; color: var(--tx-1);
}
.chart-badge {
  font-family: var(--font-display); font-size: 9px; font-weight: 600;
  letter-spacing: .12em; padding: 2px 6px;
  border: 1px solid var(--line-strong); color: var(--tx-2);
  text-transform: uppercase; background: none !important; border-radius: 0;
}
.chart-badge.green { color: var(--accent); border-color: var(--accent-line); }
.chart-badge.purple { color: var(--tx-2); }
.chart-badge.orange { color: var(--warn); border-color: var(--warn); }
.chart-badge.red { color: var(--err); border-color: var(--err); }
.chart-container { height: 260px; }

/* --- Filter Bar --- */
.filter-bar {
  display:flex; align-items:flex-end; gap: var(--sp-4);
  padding: 14px 16px; background: var(--bg-1);
  border: 1px solid var(--line); margin-bottom: var(--sp-3);
  flex-wrap: wrap;
}
.filter-group { display:flex; flex-direction:column; gap:4px; }
.filter-group label {
  font-family: var(--font-display); font-size: 9px; font-weight: 600;
  letter-spacing: .12em; color: var(--tx-3); text-transform: uppercase;
  white-space: nowrap;
}
.filter-group select, .filter-group input {
  padding: 6px 10px; background: var(--bg-0);
  border: 1px solid var(--line-strong); border-radius: 0;
  color: var(--tx-1); font-family: var(--font-body); font-size: 13px;
  cursor: pointer; outline: none; min-width: 120px;
  transition: border-color .15s;
}
.filter-group select:focus, .filter-group input:focus { border-color: var(--accent); }
.filter-search { display:flex; gap:0; flex:1; min-width: 200px; }
.filter-search input {
  flex:1; padding: 6px 10px; background: var(--bg-0);
  border: 1px solid var(--line-strong); border-radius: 0;
  color: var(--tx-1); font-family: var(--font-body); font-size: 13px; outline: none;
}
.filter-search input:focus { border-color: var(--accent); }
.filter-search input::placeholder { color: var(--tx-3); }
.btn-search {
  padding: 6px 18px; background: transparent; color: var(--accent);
  border: 1px solid var(--accent); border-radius: 0;
  font-family: var(--font-display); font-size: 12px; font-weight: 600;
  letter-spacing: .08em; cursor: pointer; transition: var(--transition);
  text-transform: uppercase;
}
.btn-search:hover { background: var(--accent); color: var(--bg-0); }

/* --- Question Stats Bar --- */
.question-stats {
  display:flex; gap: var(--sp-5); padding: 8px 16px;
  background: var(--bg-1); border: 1px solid var(--line);
  margin-bottom: var(--sp-3);
  font-family: var(--font-display); font-size: 11px; color: var(--tx-2);
  letter-spacing: .06em; text-transform: uppercase;
}
.question-stats strong {
  color: var(--accent); font-size: 13px; font-weight: 700;
}

/* --- Question List --- */
.question-list { display:flex; flex-direction:column; gap: 1px; }
.question-card {
  background: var(--bg-1); border: 1px solid var(--line);
  border-bottom: none; padding: 14px 16px; cursor: pointer;
  transition: var(--transition);
}
.question-card:last-child { border-bottom: 1px solid var(--line); }
.question-card:hover { background: var(--bg-2); border-left: 2px solid var(--accent); padding-left: 15px; }
.question-header {
  display:flex; align-items:center; gap: 10px; margin-bottom: 8px; flex-wrap: wrap;
}
.question-id {
  font-family: var(--font-display); font-size: 11px; font-weight: 700;
  color: var(--accent); background: none; padding: 0;
  border-radius: 0; border: none;
}
/* unified tag system */
.question-module, .question-type, .question-tag, .tree-badge,
.chart-badge, .stat-trend, .mastery-level, .mode-tag {
  font-family: var(--font-display); font-size: 9px; font-weight: 600;
  letter-spacing: .1em; padding: 2px 5px;
  border: 1px solid var(--line-strong); color: var(--tx-2);
  background: none !important; border-radius: 0; text-transform: uppercase;
}
.question-module { color: var(--tx-2); }
.question-type { color: var(--accent); border-color: var(--accent-line); }
/* difficulty: block chars rendered by JS */
.question-difficulty {
  display:flex; align-items:center; gap:4px;
  font-family: var(--font-display); font-size: 11px; font-weight: 600;
  letter-spacing: .04em; color: var(--tx-2);
}
.question-difficulty .lv { color: var(--accent); }
.question-difficulty .blocks { letter-spacing: 1px; color: var(--accent); }
.question-difficulty .blocks .empty { color: var(--tx-3); }
.question-difficulty .star, .question-difficulty .star.empty { display:none; }
.question-accuracy {
  margin-left: auto; font-family: var(--font-display);
  font-size: 11px; color: var(--tx-3); letter-spacing: .04em;
}
.question-stem {
  font-family: var(--font-body); font-size: 14px; line-height: 1.7;
  color: var(--tx-1); margin-bottom: 8px;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical;
  overflow: hidden;
}
.question-tags { display:flex; gap: 6px; flex-wrap: wrap; }
.question-stats-row {
  display:flex; gap: var(--sp-5); margin-top: 8px;
  padding-top: 8px; border-top: 1px solid var(--line);
  font-family: var(--font-display); font-size: 11px;
  color: var(--tx-3); letter-spacing: .04em;
}
.q-stat { display:flex; align-items:center; gap:4px; }
.q-stat-value { color: var(--tx-1); font-weight: 700; }

/* --- Modal --- */
.modal-overlay {
  display:none; position:fixed; inset: 0;
  background: rgba(0,0,0,.85); z-index: 200;
  justify-content:center; align-items:center; padding: 24px;
}
.modal-overlay.active { display:flex; }
.modal {
  background: var(--bg-1); border: 1px solid var(--accent-line);
  max-width: 800px; width: 100%; max-height: 85vh; overflow-y: auto;
  box-shadow: none; border-radius: 0; position: relative;
}
/* corner tick decoration */
.modal::before, .modal::after {
  content:''; position:absolute; width:10px; height:10px;
  border-color: var(--accent); border-style: solid;
}
.modal::before { top:-1px; left:-1px; border-width: 1px 0 0 1px; }
.modal::after { bottom:-1px; right:-1px; border-width: 0 1px 1px 0; }
.modal-header {
  display:flex; align-items:center; justify-content: space-between;
  padding: 16px 20px; border-bottom: 1px solid var(--line);
}
.modal-header h3 {
  font-family: var(--font-body); font-size: 14px; font-weight: 600;
  letter-spacing: .04em;
}
.modal-close {
  width: auto; height: auto; padding: 4px 8px;
  border: 1px solid var(--line-strong); background: transparent;
  color: var(--tx-2); border-radius: 0;
  font-family: var(--font-display); font-size: 11px; font-weight: 600;
  cursor: pointer; letter-spacing: .06em; transition: var(--transition);
}
.modal-close:hover { border-color: var(--err); color: var(--err); background: none; }
.modal-body { padding: 20px; }
.modal-body .detail-section { margin-bottom: 16px; }
.modal-body .detail-label {
  font-family: var(--font-display); font-size: 9px; color: var(--tx-3);
  margin-bottom: 6px; text-transform: uppercase; letter-spacing: .12em; font-weight: 600;
}
.modal-body .detail-content {
  font-family: var(--font-body); font-size: 14px; line-height: 1.7;
}
.modal-body .options-list { display:flex; flex-direction:column; gap: 6px; }
.modal-body .option-item {
  display:flex; gap: 8px; padding: 8px 12px; border-radius: 0;
  background: var(--bg-2); border: 1px solid var(--line);
}
.modal-body .option-label {
  font-family: var(--font-display); font-weight: 700; color: var(--accent);
  min-width: 20px; font-size: 13px;
}
.modal-body .answer-box {
  padding: 10px 14px; background: none;
  border: 1px solid var(--line); border-left: 2px solid var(--accent);
  border-radius: 0; color: var(--tx-1); font-weight: 600;
}
.modal-body .analysis-box {
  padding: 10px 14px; background: none;
  border: 1px solid var(--line); border-left: 2px solid var(--tx-2);
  border-radius: 0; color: var(--tx-1);
}

/* --- 2027 Knowledge Checklist --- */
.knowledge-cover {
  display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 48px;
  align-items: end; padding: 42px;
  margin-bottom: 12px; border: 1px solid var(--line);
  background:
    linear-gradient(135deg, var(--accent-dim), transparent 46%),
    var(--bg-1);
}
.knowledge-eyebrow {
  display: block; margin-bottom: 18px;
  font-family: var(--font-display); font-size: 10px; font-weight: 700;
  color: var(--accent); letter-spacing: .18em;
}
.knowledge-cover h2 {
  font-family: var(--font-display); font-size: clamp(34px, 5vw, 64px);
  font-weight: 600; line-height: 1.02; letter-spacing: -.04em;
}
.knowledge-cover h2 span { color: var(--accent); }
.knowledge-cover p {
  max-width: 680px; margin-top: 20px; color: var(--tx-2);
  font-size: 14px; line-height: 1.8;
}
.knowledge-cover-stats {
  display: grid; grid-template-columns: repeat(3, minmax(90px, 1fr));
  border: 1px solid var(--line); min-width: 330px;
}
.knowledge-cover-stats div {
  padding: 18px 16px; border-right: 1px solid var(--line);
}
.knowledge-cover-stats div:last-child { border-right: none; }
.knowledge-cover-stats strong {
  display: block; font-family: var(--font-display); font-size: 26px;
  color: var(--accent); line-height: 1;
}
.knowledge-cover-stats span {
  display: block; margin-top: 8px; font-size: 11px; color: var(--tx-3);
}
.knowledge-actions {
  display: flex; align-items: end; gap: 8px; padding: 12px 14px;
  border: 1px solid var(--line); border-bottom: none; background: var(--bg-1);
}
.knowledge-search {
  display: flex; flex-direction: column; gap: 5px; flex: 1;
  font-family: var(--font-display); font-size: 9px; color: var(--tx-3);
  letter-spacing: .12em;
}
.knowledge-search input {
  width: 100%; padding: 9px 11px; color: var(--tx-1);
  background: var(--bg-0); border: 1px solid var(--line-strong);
  font-family: var(--font-body); outline: none;
}
.knowledge-search input:focus { border-color: var(--accent); }
.knowledge-layout {
  display:grid; grid-template-columns: 280px minmax(0, 1fr); gap: 0;
  border: 1px solid var(--line);
}
.knowledge-tree-panel {
  background: var(--bg-1); border-right: 1px solid var(--line);
  overflow: hidden; border-radius: 0; align-self: start;
  position: sticky; top: 76px;
}
.tree-toolbar {
  display:flex; gap: 6px; padding: 10px 14px;
  border-bottom: 1px solid var(--line);
  font-family: var(--font-display); font-size: 10px; font-weight: 700;
  color: var(--tx-3); letter-spacing: .12em;
}
.btn-sm {
  padding: 5px 10px; background: transparent;
  border: 1px solid var(--line-strong); border-radius: 0;
  color: var(--tx-2); font-family: var(--font-display); font-size: 10px;
  font-weight: 600; letter-spacing: .08em; cursor: pointer;
  text-transform: uppercase; transition: var(--transition);
}
.btn-sm:hover { border-color: var(--accent); color: var(--accent); }
.knowledge-tree { padding: 10px; max-height: calc(100vh - 170px); overflow-y: auto; }
.tree-node { margin-bottom: 1px; }
.tree-node-content {
  display:flex; align-items:center; gap: 8px;
  padding: 7px 10px; border-radius: 0; cursor: pointer;
  transition: var(--transition); font-size: 13px;
  font-family: var(--font-body);
}
.tree-node-content:hover { background: var(--bg-2); }
.tree-node-content.selected {
  background: var(--accent-dim); color: var(--accent);
  border-left: 2px solid var(--accent); padding-left: 8px;
}
.tree-toggle {
  width: 18px; height: 18px; display:flex; align-items:center; justify-content:center;
  font-family: var(--font-display); font-size: 10px; font-weight: 700;
  color: var(--tx-3); cursor: pointer; flex-shrink: 0; transition: var(--transition);
}
.tree-toggle:hover { color: var(--accent); }
.tree-icon { display:none; } /* emoji removed */
.tree-label { flex: 1; }
.tree-node-id {
  font-family: var(--font-display); font-size: 9px; font-weight: 600;
  color: var(--tx-3); letter-spacing: .04em;
}
.tree-badge.high { color: var(--err); border-color: var(--err); }
.tree-badge.medium { color: var(--warn); border-color: var(--warn); }
.tree-badge.low { color: var(--tx-3); }
.tree-children {
  margin-left: 14px; border-left: 1px dashed var(--line-dash); padding-left: 6px;
}
.tree-children.collapsed { display: none; }
.knowledge-document-panel { min-width: 0; background: var(--bg-0); }
.knowledge-document { padding: 22px; }
.knowledge-module-card {
  margin-bottom: 24px; border: 1px solid var(--line); background: var(--bg-1);
}
.knowledge-module-heading {
  display: flex; align-items: center; gap: 18px; padding: 24px;
  border-bottom: 1px solid var(--line); cursor: pointer;
}
.knowledge-module-heading.selected { background: var(--accent-dim); }
.knowledge-module-number {
  font-family: var(--font-display); font-size: 32px; line-height: 1;
  color: var(--accent); font-weight: 700;
}
.knowledge-module-heading p {
  margin-bottom: 5px; font-family: var(--font-display); font-size: 9px;
  color: var(--tx-3); letter-spacing: .13em;
}
.knowledge-module-heading h3 {
  font-family: var(--font-display); font-size: 23px; font-weight: 600;
}
.knowledge-section-body { padding: 12px; }
.knowledge-section-body.collapsed,
.knowledge-chapter-content.collapsed { display: none; }
.knowledge-chapter-card {
  margin-bottom: 10px; border: 1px solid var(--line);
  background: var(--bg-0);
}
.knowledge-chapter-card:last-child { margin-bottom: 0; }
.knowledge-chapter-heading {
  display: flex; justify-content: space-between; align-items: center;
  width: 100%; padding: 16px; border: none; border-bottom: 1px solid var(--line);
  background: transparent; color: var(--tx-1); text-align: left; cursor: pointer;
}
.knowledge-chapter-heading.selected { background: var(--accent-dim); }
.knowledge-chapter-heading span { display: flex; flex-direction: column; gap: 4px; }
.knowledge-chapter-heading small,
.knowledge-group-title small,
.knowledge-leaf-code {
  font-family: var(--font-display); font-size: 9px; color: var(--tx-3);
  letter-spacing: .09em;
}
.knowledge-chapter-heading strong { font-size: 15px; font-weight: 600; }
.knowledge-chapter-heading em {
  color: var(--tx-3); font-family: var(--font-display); font-size: 10px;
  font-style: normal;
}
.knowledge-chapter-content { padding: 12px; }
.knowledge-group { margin-bottom: 12px; }
.knowledge-group:last-child { margin-bottom: 0; }
.knowledge-group-title {
  display: flex; justify-content: space-between; width: 100%;
  padding: 10px 12px; color: var(--tx-1); background: var(--bg-2);
  border: 1px solid var(--line); cursor: pointer; text-align: left;
}
.knowledge-group-title.selected { border-color: var(--accent); color: var(--accent); }
.knowledge-leaf-grid {
  display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px;
  margin-top: 1px;
}
.knowledge-leaf-card {
  display: flex; flex-direction: column; align-items: flex-start; gap: 7px;
  min-height: 112px; padding: 15px; color: var(--tx-1); background: var(--bg-1);
  border: 1px solid var(--line); cursor: pointer; text-align: left;
  transition: border-color .15s, background .15s, transform .15s;
}
.knowledge-leaf-card:hover {
  border-color: var(--accent-line); background: var(--accent-dim);
  transform: translateY(-1px);
}
.knowledge-leaf-card.selected {
  border-color: var(--accent); background: var(--accent-dim);
}
.knowledge-leaf-card strong { flex: 1; font-size: 14px; line-height: 1.5; }
.knowledge-leaf-meta {
  display: flex; align-items: center; gap: 8px;
  font-family: var(--font-display); font-size: 9px; color: var(--tx-3);
}
.knowledge-frequency {
  padding: 2px 5px; border: 1px solid var(--line-strong);
}
.knowledge-frequency.high { color: var(--err); border-color: var(--err); }
.knowledge-frequency.medium { color: var(--warn); border-color: var(--warn); }
.knowledge-frequency.low { color: var(--tx-3); }
.knowledge-no-results { padding: 28px 12px; color: var(--tx-3); text-align: center; }
.knowledge-no-results.large { padding: 90px 20px; }
.knowledge-detail-panel {
  background: var(--bg-1); border-radius: 0; padding: 24px;
  min-height: 260px; border-top: 1px solid var(--line);
}
.knowledge-detail-heading { margin-bottom: 24px; }
.knowledge-detail-heading > span {
  font-family: var(--font-display); font-size: 10px; color: var(--accent);
  letter-spacing: .12em;
}
.knowledge-detail-heading h3 {
  margin: 7px 0; font-family: var(--font-display); font-size: 26px;
}
.knowledge-detail-heading p { color: var(--tx-2); font-size: 13px; }
.detail-empty {
  display:flex; flex-direction:column; align-items:center; justify-content:center;
  height: 400px; color: var(--tx-3);
  font-family: var(--font-display); font-size: 14px; letter-spacing: .08em;
}
.empty-icon { display:none; }
.detail-section { margin-bottom: 16px; }
.detail-section h4 {
  font-family: var(--font-display); font-size: 10px; font-weight: 700;
  margin-bottom: 10px; color: var(--accent);
  letter-spacing: .12em; text-transform: uppercase;
}
.detail-info-grid { display:grid; grid-template-columns: repeat(3,1fr); gap: 0; border: 1px solid var(--line); }
.detail-info-item {
  padding: 10px 12px; background: none; border-radius: 0;
  border-right: 1px solid var(--line);
}
.detail-info-item:last-child { border-right: none; }
.detail-info-label {
  font-family: var(--font-display); font-size: 9px; font-weight: 600;
  color: var(--tx-3); margin-bottom: 4px; letter-spacing: .12em; text-transform: uppercase;
}
.detail-info-value {
  font-family: var(--font-display); font-size: 13px; font-weight: 700;
  color: var(--tx-1);
}
.kp-children-list { display:flex; flex-direction:column; gap: 1px; }
.kp-child-item {
  display:flex; align-items:center; gap: 8px;
  padding: 8px 10px; background: var(--bg-2); border-radius: 0;
  font-size: 13px; font-family: var(--font-body);
  border: 1px solid var(--line); border-bottom: none;
  width: 100%; color: var(--tx-1); text-align: left; cursor: pointer;
}
.kp-child-item:last-child { border-bottom: 1px solid var(--line); }
.kp-child-level {
  font-family: var(--font-display); font-size: 9px; font-weight: 600;
  padding: 1px 4px; border: 1px solid var(--line-strong);
  color: var(--tx-3); border-radius: 0; background: none;
  letter-spacing: .06em;
}

/* --- Student Analytics Page --- */
.student-selector { margin-bottom: var(--sp-5); }
.student-cards { display:grid; grid-template-columns: repeat(3,1fr); gap: 0; border: 1px solid var(--line); }
.student-card {
  background: var(--bg-1); border-right: 1px solid var(--line);
  border-radius: 0; padding: 16px; cursor: pointer;
  transition: var(--transition); text-align: center;
}
.student-card:last-child { border-right: none; }
.student-card:hover { background: var(--bg-2); }
.student-card.selected {
  border-left: 2px solid var(--accent); background: var(--accent-dim);
}
.student-avatar {
  width: 48px; height: 48px; margin: 0 auto 8px;
  border: 1px solid var(--line-strong); border-radius: 0;
  display:flex; align-items:center; justify-content:center;
  font-family: var(--font-display); font-size: 18px; font-weight: 700;
  color: var(--tx-1); background: transparent;
}
.student-name {
  font-family: var(--font-body); font-size: 14px; font-weight: 600;
  margin-bottom: 2px;
}
.student-class {
  font-family: var(--font-display); font-size: 10px; color: var(--tx-3);
  margin-bottom: 10px; letter-spacing: .06em;
}
.student-quick-stats { display:flex; justify-content:center; gap: var(--sp-5); }
.student-quick-stat { text-align:center; }
.student-quick-stat .value {
  font-family: var(--font-display); font-size: 16px; font-weight: 700;
  color: var(--accent);
}
.student-quick-stat .label {
  font-family: var(--font-display); font-size: 9px; font-weight: 600;
  color: var(--tx-3); letter-spacing: .12em; text-transform: uppercase;
}

/* --- Mastery List --- */
.knowledge-mastery-list {
  max-height: 280px; overflow-y: auto;
  display:flex; flex-direction:column; gap: 1px;
}
.mastery-item {
  display:flex; align-items:center; gap: 10px;
  padding: 8px 10px; background: var(--bg-2); border-radius: 0;
  border: 1px solid var(--line); border-bottom: none;
}
.mastery-item:last-child { border-bottom: 1px solid var(--line); }
.mastery-bar {
  flex:1; height: 6px; background: var(--bg-3);
  border-radius: 0; overflow: hidden; border: 1px solid var(--line);
}
.mastery-fill { height: 100%; border-radius: 0; transition: width .8s ease; }
.mastery-name {
  min-width: 120px; font-size: 12px; font-family: var(--font-body);
}
.mastery-score {
  min-width: 36px; text-align:right;
  font-family: var(--font-display); font-size: 13px; font-weight: 700; color: var(--tx-1);
}
.mastery-level {
  min-width: 64px; text-align:center; font-size: 9px; padding: 2px 5px;
}

/* --- Weak Points --- */
.weak-points-list { display:flex; flex-direction:column; gap: 1px; }
.weak-point-card {
  display:flex; gap: 14px; padding: 14px; background: var(--bg-2);
  border-radius: 0; border: 1px solid var(--line); border-bottom: none;
  border-left: 2px solid;
}
.weak-point-card:last-child { border-bottom: 1px solid var(--line); }
.weak-point-card.P0 { border-left-color: var(--err); }
.weak-point-card.P1 { border-left-color: var(--warn); }
.weak-point-card.P2 { border-left-color: var(--tx-2); }
.weak-priority {
  width: auto; height: auto; padding: 4px 8px; border-radius: 0;
  display:flex; align-items:center; justify-content:center;
  font-family: var(--font-display); font-size: 11px; font-weight: 700;
  flex-shrink: 0; border: 1px solid; background: none !important;
  letter-spacing: .06em; min-width: 36px;
}
.weak-priority.P0 { color: var(--err); border-color: var(--err); }
.weak-priority.P1 { color: var(--warn); border-color: var(--warn); }
.weak-priority.P2 { color: var(--tx-2); border-color: var(--tx-2); }
.weak-info { flex: 1; }
.weak-name { font-size: 14px; font-weight: 600; margin-bottom: 2px; font-family: var(--font-body); }
.weak-module {
  font-family: var(--font-display); font-size: 10px; color: var(--tx-3);
  margin-bottom: 6px; letter-spacing: .06em; text-transform: uppercase;
}
.weak-reason { font-size: 12px; color: var(--tx-2); line-height: 1.6; font-family: var(--font-body); }
.weak-score { text-align:center; flex-shrink: 0; }
.weak-score .score-value {
  font-family: var(--font-display); font-size: 22px; font-weight: 700;
  color: var(--err);
}
.weak-score .score-label {
  font-family: var(--font-display); font-size: 9px; color: var(--tx-3);
  letter-spacing: .12em; text-transform: uppercase;
}

/* --- Recommendations --- */
.recommendations { display:flex; flex-direction:column; gap: 1px; }
.rec-card {
  display:flex; align-items:center; gap: 14px; padding: 14px;
  background: var(--bg-2); border-radius: 0;
  border: 1px solid var(--line); border-bottom: none;
}
.rec-card:last-child { border-bottom: 1px solid var(--line); }
.rec-rank {
  width: auto; height: auto; min-width: 32px; padding: 4px 6px;
  border-radius: 0; background: none !important;
  border: 1px solid var(--line-strong); color: var(--tx-3);
  display:flex; align-items:center; justify-content:center;
  font-family: var(--font-display); font-size: 12px; font-weight: 700;
  flex-shrink: 0; letter-spacing: .04em;
}
.rec-info { flex: 1; }
.rec-name { font-size: 14px; font-weight: 600; margin-bottom: 2px; font-family: var(--font-body); }
.rec-reason { font-family: var(--font-display); font-size: 10px; color: var(--tx-3); letter-spacing: .04em; }
.rec-meta { display:flex; gap: var(--sp-4); flex-shrink: 0; }
.rec-meta-item { text-align:center; }
.rec-meta-item .value {
  font-family: var(--font-display); font-size: 13px; font-weight: 700; color: var(--tx-1);
}
.rec-meta-item .label {
  font-family: var(--font-display); font-size: 9px; color: var(--tx-3);
  letter-spacing: .12em; text-transform: uppercase;
}

/* --- Error Table --- */
.error-table-wrapper { overflow-x: auto; border: 1px solid var(--line); }
.error-table { width: 100%; border-collapse: collapse; }
.error-table th {
  text-align: left; padding: 10px 14px;
  font-family: var(--font-display); font-size: 9px; font-weight: 700;
  color: var(--tx-3); border-bottom: 1px solid var(--line);
  text-transform: uppercase; letter-spacing: .12em;
  background: var(--bg-1);
}
.error-table td {
  padding: 10px 14px; font-size: 13px;
  border-bottom: 1px solid var(--line); font-family: var(--font-body);
}
.error-table tr:last-child td { border-bottom: none; }
.error-table tr:hover td { background: var(--bg-2); }
.error-rank {
  width: auto; height: auto; min-width: 24px; padding: 2px 4px;
  border-radius: 0; display: inline-flex; align-items:center; justify-content:center;
  font-family: var(--font-display); font-size: 11px; font-weight: 700;
  border: 1px solid var(--line-strong); background: none !important;
  letter-spacing: .04em;
}
.error-rank.top1, .error-rank.top2, .error-rank.top3 {
  color: var(--accent); border-color: var(--accent-line);
}
.error-rank.normal { color: var(--tx-3); border-color: var(--line-strong); }
.error-rate-bar { display:flex; align-items:center; gap: 8px; }
.error-rate-fill {
  width: 60px; height: 6px; background: var(--bg-3);
  border-radius: 0; overflow: hidden; border: 1px solid var(--line);
}
.error-rate-fill .fill { height: 100%; border-radius: 0; }
.error-rate-text {
  font-family: var(--font-display); font-weight: 700; min-width: 36px;
  font-size: 12px; letter-spacing: .04em;
}

/* --- Footer --- */
.footer {
  padding: 16px 20px; text-align: center;
  font-family: var(--font-display); font-size: 10px; color: var(--tx-3);
  border-top: 1px solid var(--line); margin-top: 40px;
  letter-spacing: .12em; text-transform: uppercase;
}

/* --- KaTeX (must NOT inherit sans-serif stack) --- */
.katex {
  font-size: 1.05em;
  font-family: KaTeX_Main, "Times New Roman", serif !important;
  color: var(--tx-1);
}
.katex-display { margin: 8px 0; overflow-x: auto; overflow-y: hidden; padding: 4px 0; }

/* --- Scrollbar --- */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: var(--bg-0); }
::-webkit-scrollbar-thumb { background: var(--line-strong); border-radius: 0; }
::-webkit-scrollbar-thumb:hover { background: var(--accent-line); }

/* --- Grid option grid fallback disabled --- */
.no-grid body { background-image: none; }

/* --- Responsive --- */
@media (max-width: 1024px) {
  .stats-grid { grid-template-columns: repeat(2,1fr); }
  .stats-grid .stat-card:nth-child(2) { border-right: none; }
  .charts-row { grid-template-columns: 1fr; }
  .knowledge-layout { grid-template-columns: 1fr; }
  .knowledge-tree-panel {
    position: static; border-right: none; border-bottom: 1px solid var(--line);
  }
  .knowledge-tree { max-height: 320px; }
  .knowledge-cover { grid-template-columns: 1fr; gap: 28px; }
  .knowledge-cover-stats { min-width: 0; }
  .student-cards { grid-template-columns: 1fr; }
  .student-card { border-right: none; border-bottom: 1px solid var(--line); }
}
@media (max-width: 768px) {
  .navbar { flex-wrap: wrap; height: auto; padding: 10px 16px; }
  .nav-tabs { order: 3; width: 100%; margin-top: 8px; }
  .nav-tab { flex: 1; padding: 10px 4px; align-items: center; }
  .nav-tab .tab-label { font-size: 11px; }
  .stats-grid { grid-template-columns: 1fr; }
  .stats-grid .stat-card { border-right: none; border-bottom: 1px solid var(--line); }
  .filter-bar { flex-direction: column; align-items: stretch; }
  .filter-group { flex-direction: row; align-items: center; }
  .main-content { padding: 16px; }
  .chart-container { height: 220px; }
  .knowledge-cover { padding: 26px 20px; }
  .knowledge-cover h2 { font-size: 38px; }
  .knowledge-cover-stats { grid-template-columns: 1fr; }
  .knowledge-cover-stats div {
    display: flex; justify-content: space-between; align-items: center;
    border-right: none; border-bottom: 1px solid var(--line);
  }
  .knowledge-cover-stats div:last-child { border-bottom: none; }
  .knowledge-cover-stats span { margin-top: 0; }
  .knowledge-actions { flex-wrap: wrap; }
  .knowledge-search { flex-basis: 100%; }
  .knowledge-document { padding: 12px; }
  .knowledge-leaf-grid { grid-template-columns: 1fr; }
  .knowledge-module-heading { padding: 18px; }
  .knowledge-detail-panel { padding: 18px; }
}

/* --- Review Queue --- */
.review-list { display: flex; flex-direction: column; gap: 4px; }
.review-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 16px; border-bottom: 1px solid var(--line);
  cursor: pointer; transition: background .15s;
  font-family: var(--font-body);
}
.review-item:hover { background: var(--accent-dim); }
.review-item-left { display: flex; align-items: center; gap: 12px; min-width: 180px; }
.review-item-center { flex: 1; display: flex; flex-direction: column; gap: 4px; }
.review-item-right { display: flex; align-items: center; gap: 12px; min-width: 140px; justify-content: flex-end; }
.review-badge {
  font-family: var(--font-display); font-size: 11px; letter-spacing: .06em;
  padding: 2px 8px; border: 1px solid;
}
.review-badge.question { color: var(--warn); border-color: var(--warn); }
.review-badge.method { color: var(--accent); border-color: var(--accent); }
.review-id { font-family: var(--font-display); font-size: 13px; color: var(--accent); }
.review-preview { font-size: 14px; color: var(--tx-1); }
.review-source { font-size: 11px; color: var(--tx-3); font-family: var(--font-display); }
.review-confidence { font-family: var(--font-display); font-size: 14px; font-weight: 500; }
.review-module { font-size: 12px; color: var(--tx-2); }

/* Review Detail */
.review-actions { display: flex; gap: 8px; }
.review-actions button {
  font-family: var(--font-display); font-size: 12px; letter-spacing: .06em;
  padding: 6px 16px; border: 1px solid var(--line-strong); background: var(--bg-2);
  color: var(--tx-1); cursor: pointer; transition: all .15s;
}
.btn-approve { border-color: var(--accent); color: var(--accent); }
.btn-approve:hover { background: var(--accent-dim); }
.btn-reject { border-color: var(--err); color: var(--err); }
.btn-reject:hover { background: rgba(255,69,58,.08); }
.btn-edit { border-color: var(--warn); color: var(--warn); }
.btn-edit:hover { background: var(--accent-dim); }

.review-detail-content { padding: 20px 0; }

/* Detail Grid (shared between review & method) */
.detail-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px 24px; margin-bottom: 20px; }
.detail-row { display: flex; align-items: baseline; gap: 12px; }
.detail-label { font-family: var(--font-display); font-size: 11px; color: var(--tx-3); letter-spacing: .06em; min-width: 100px; }
.detail-value { font-size: 14px; color: var(--tx-1); }

.detail-section { margin-bottom: 16px; border-top: 1px solid var(--line); padding-top: 12px; }
.detail-section h4 { font-family: var(--font-display); font-size: 11px; color: var(--accent); letter-spacing: .12em; margin-bottom: 8px; }
.detail-text { font-size: 14px; color: var(--tx-1); line-height: 1.7; }
.detail-text .katex { font-size: 1em; }

.detail-options { display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px; }
.detail-option { display: flex; align-items: baseline; gap: 8px; padding: 6px 10px; border-bottom: 1px solid var(--line); }
.opt-label { font-family: var(--font-display); font-size: 14px; color: var(--accent); font-weight: 500; }
.opt-content { font-size: 14px; color: var(--tx-1); }

.detail-steps { display: flex; flex-direction: column; gap: 8px; }
.detail-step { display: flex; align-items: flex-start; gap: 12px; }
.step-num { font-family: var(--font-display); font-size: 13px; color: var(--accent); min-width: 24px; text-align: right; }
.step-text { font-size: 14px; color: var(--tx-1); line-height: 1.6; }

.detail-formula { padding: 8px 12px; border-left: 2px solid var(--accent); margin-bottom: 6px; font-size: 14px; color: var(--tx-1); }
.detail-warnings { display: flex; flex-direction: column; gap: 6px; }
.detail-warning { padding: 6px 12px; border-left: 2px solid var(--err); font-size: 13px; color: var(--tx-2); }

.detail-tags { display: flex; gap: 6px; flex-wrap: wrap; }
.detail-tags .tag { font-family: var(--font-display); font-size: 11px; }

/* --- Methods List --- */
.methods-list { display: flex; flex-direction: column; gap: 4px; }
.method-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 16px; border-bottom: 1px solid var(--line);
  cursor: pointer; transition: background .15s;
  font-family: var(--font-body);
}
.method-item:hover { background: var(--accent-dim); }
.method-item-left { display: flex; align-items: center; gap: 12px; min-width: 180px; }
.method-item-center { flex: 1; display: flex; align-items: center; gap: 12px; }
.method-item-right { display: flex; align-items: center; gap: 12px; min-width: 140px; justify-content: flex-end; }
.method-id { font-family: var(--font-display); font-size: 13px; color: var(--accent); }
.method-name { font-size: 14px; color: var(--tx-1); font-weight: 500; }
.method-category { font-family: var(--font-display); font-size: 11px; color: var(--warn); letter-spacing: .06em; }
.method-module { font-size: 12px; color: var(--tx-2); }
.method-linked { font-family: var(--font-display); font-size: 11px; color: var(--tx-3); }
.method-difficulty { font-family: var(--font-display); font-size: 11px; color: var(--tx-2); }

.method-detail-content { padding: 20px 0; }

/* ===== UPLOAD :: 处理管线 ===== */
.pipeline-bar {
  display: flex; align-items: center; gap: 0;
  background: var(--bg-1); border: 1px solid var(--line);
  padding: 16px 20px; margin-bottom: 20px;
}
.pipeline-step {
  display: flex; align-items: center; gap: 8px;
  padding: 8px 16px; font-family: var(--font-body);
}
.pipe-num { font-family: var(--font-display); font-size: 13px; color: var(--accent); }
.pipe-label { font-family: var(--font-display); font-size: 12px; color: var(--tx-2); letter-spacing: .08em; }
.pipe-status { font-family: var(--font-display); font-size: 11px; color: var(--tx-3); }
.pipe-status.active { color: var(--accent); }
.pipe-status.done { color: var(--accent); }
.pipe-status.error { color: var(--err); }
.pipeline-connector {
  width: 40px; height: 1px; background: var(--line);
}
.pipeline-connector.active { background: var(--accent); }

/* ===== UPLOAD :: 上传区域 ===== */
.upload-zone {
  border: 2px dashed var(--line); background: var(--bg-1);
  padding: 60px 40px; text-align: center;
  cursor: pointer; transition: border-color .2s, background .2s;
  margin-bottom: 20px;
}
.upload-zone:hover, .upload-zone.drag-over {
  border-color: var(--accent); background: var(--accent-dim);
}
.upload-icon {
  font-family: var(--font-display); font-size: 18px; color: var(--accent);
  margin-bottom: 12px; letter-spacing: .1em;
}
.upload-sub { font-size: 13px; color: var(--tx-3); margin-bottom: 16px; }
.upload-types {
  display: flex; justify-content: center; gap: 12px;
  font-family: var(--font-display); font-size: 11px; color: var(--tx-3);
}

/* ===== UPLOAD :: 文件列表 ===== */
.file-list { max-height: 300px; overflow-y: auto; }
.file-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 10px 16px; border-bottom: 1px solid var(--line);
  font-family: var(--font-body); cursor: default;
}
.file-item-left { display: flex; align-items: center; gap: 12px; min-width: 200px; }
.file-ext { font-family: var(--font-display); font-size: 11px; color: var(--accent); padding: 2px 6px; border: 1px solid var(--accent); }
.file-name { font-size: 13px; color: var(--tx-1); max-width: 300px; overflow: hidden; text-overflow: ellipsis; }
.file-size { font-family: var(--font-display); font-size: 11px; color: var(--tx-3); }
.file-status { font-family: var(--font-display); font-size: 11px; }
.file-status.pending { color: var(--tx-3); }
.file-status.processing { color: var(--warn); }
.file-status.done { color: var(--accent); }
.file-status.error { color: var(--err); }
.upload-actions { display: flex; gap: 8px; }

/* ===== UPLOAD :: 提取结果 ===== */
.results-list { max-height: 400px; overflow-y: auto; }
.result-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 16px; border-bottom: 1px solid var(--line);
  cursor: pointer; transition: background .15s;
}
.result-item:hover { background: var(--accent-dim); }
.result-badge { font-family: var(--font-display); font-size: 11px; padding: 2px 8px; border: 1px solid; }
.result-badge.question { border-color: var(--accent); color: var(--accent); }
.result-badge.method { border-color: var(--warn); color: var(--warn); }
.result-preview { font-size: 13px; color: var(--tx-1); max-width: 400px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.result-confidence { font-family: var(--font-display); font-size: 11px; }
.result-confidence.high { color: var(--accent); }
.result-confidence.mid { color: var(--warn); }
.result-confidence.low { color: var(--err); }

/* ===== FORMAT EDITOR ===== */
.editor-form { padding: 20px 0; }
.form-grid {
  display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 16px; margin-bottom: 16px;
}
.form-field { display: flex; flex-direction: column; gap: 6px; }
.form-field.full-width { grid-column: 1 / -1; }
.form-field label {
  font-family: var(--font-display); font-size: 11px;
  color: var(--tx-2); letter-spacing: .06em;
}
.form-field input, .form-field select, .form-field textarea {
  background: var(--bg-1); border: 1px solid var(--line);
  padding: 8px 12px; color: var(--tx-1);
  font-family: var(--font-body); font-size: 13px;
  border-radius: 0; outline: none;
  transition: border-color .2s;
}
.form-field input:focus, .form-field select:focus, .form-field textarea:focus {
  border-color: var(--accent);
}
.field-readonly { color: var(--tx-3); cursor: not-allowed; }
.latex-preview {
  padding: 12px 16px; background: var(--bg-2);
  border: 1px solid var(--line); margin-top: 4px;
  font-size: 14px; color: var(--tx-1); min-height: 40px;
}

/* ===== 选项编辑 ===== */
.options-grid { display: flex; flex-direction: column; gap: 8px; }
.option-row { display: flex; align-items: center; gap: 8px; }
.option-label { font-family: var(--font-display); font-size: 13px; color: var(--accent); min-width: 20px; }
.option-input { flex: 1; background: var(--bg-1); border: 1px solid var(--line); padding: 6px 10px; color: var(--tx-1); font-family: var(--font-body); }

/* ===== 步骤编辑 ===== */
.steps-editor { display: flex; flex-direction: column; gap: 8px; }
.step-row { display: flex; align-items: center; gap: 8px; }
.step-num { font-family: var(--font-display); font-size: 12px; color: var(--accent); min-width: 24px; }
.step-input { flex: 1; background: var(--bg-1); border: 1px solid var(--line); padding: 6px 10px; color: var(--tx-1); font-family: var(--font-body); }

/* ===== 通用按钮 ===== */
.btn-accent {
  background: transparent; border: 1px solid var(--accent);
  padding: 6px 16px; color: var(--accent);
  font-family: var(--font-display); font-size: 12px;
  letter-spacing: .06em; cursor: pointer;
  transition: background .2s;
}
.btn-accent:hover { background: var(--accent-dim); }
.btn-ghost {
  background: transparent; border: 1px solid var(--line);
  padding: 6px 16px; color: var(--tx-2);
  font-family: var(--font-display); font-size: 12px;
  letter-spacing: .06em; cursor: pointer;
  transition: background .2s;
}
.btn-ghost:hover { background: var(--bg-2); }

/* ===== BLOG ===== */
.blog-header h2 {
  font-family: var(--font-display); font-size: 18px;
  color: var(--accent); letter-spacing: .08em;
  margin-bottom: 16px;
}
.blog-filter-bar {
  display: flex; align-items: center; gap: 16px;
  padding: 12px 0; border-bottom: 1px solid var(--line);
  margin-bottom: 20px;
}
.blog-stats-strip {
  font-family: var(--font-display); font-size: 12px;
  color: var(--tx-2); margin-left: auto;
}
.blog-list {
  display: grid; gap: 12px;
}
.blog-card {
  display: grid; grid-template-columns: 80px 1fr;
  gap: 16px; padding: 16px;
  border: 1px solid var(--line);
  background: var(--bg-1); cursor: pointer;
  transition: border-color .15s;
}
.blog-card:hover { border-color: var(--accent); }
.blog-card-meta {
  font-family: var(--font-display); font-size: 11px;
  color: var(--tx-3); display: flex; flex-direction: column;
  gap: 6px;
}
.blog-card-meta .blog-label {
  color: var(--accent); font-size: 13px;
  font-weight: 600;
}
.blog-card-body h3 {
  font-size: 16px; color: var(--tx-1);
  margin-bottom: 8px; line-height: 1.4;
}
.blog-card-body .blog-excerpt {
  font-size: 13px; color: var(--tx-2);
  line-height: 1.5; margin-bottom: 8px;
}
.blog-card-tags { display: flex; gap: 6px; }
.blog-detail { padding: 20px 0; }
.blog-detail-back {
  font-family: var(--font-display); font-size: 12px;
  color: var(--accent); cursor: pointer;
  margin-bottom: 20px; display: inline-block;
}
.blog-detail-back:hover { opacity: .8; }
.blog-detail-meta {
  display: flex; gap: 12px; align-items: center;
  margin-bottom: 16px; font-family: var(--font-display);
  font-size: 12px; color: var(--tx-2);
}
.blog-detail h2 {
  font-size: 22px; color: var(--tx-1);
  margin-bottom: 20px; line-height: 1.4;
}
.blog-detail-content {
  font-size: 14px; color: var(--tx-1);
  line-height: 1.8; max-width: 720px;
}
.blog-detail-content h3 {
  font-family: var(--font-display); font-size: 16px;
  color: var(--accent); margin: 24px 0 12px;
}
.blog-detail-content p { margin-bottom: 12px; }
.blog-detail-content code {
  font-family: var(--font-display); font-size: 12px;
  background: var(--bg-2); color: var(--accent);
  padding: 2px 6px;
}
.blog-detail-content pre {
  background: var(--bg-2); border: 1px solid var(--line);
  padding: 12px 16px; margin: 16px 0;
  overflow-x: auto; font-family: var(--font-display);
  font-size: 13px; color: var(--tx-1);
}
.blog-detail-content table {
  width: 100%; border-collapse: collapse;
  margin: 16px 0; font-size: 13px;
}
.blog-detail-content th,
.blog-detail-content td {
  border: 1px solid var(--line); padding: 8px 12px;
  text-align: left;
}
.blog-detail-content th {
  background: var(--bg-2); color: var(--accent);
  font-family: var(--font-display); font-size: 11px;
}

/* ===== ABOUT ===== */
.about-header h2 {
  font-family: var(--font-display); font-size: 18px;
  color: var(--accent); letter-spacing: .08em;
  margin-bottom: 24px;
}
.about-content { max-width: 640px; }
.about-section {
  margin-bottom: 32px;
  border-bottom: 1px solid var(--line);
  padding-bottom: 24px;
}
.about-section h3 {
  font-family: var(--font-display); font-size: 14px;
  color: var(--accent); margin-bottom: 12px;
  letter-spacing: .06em;
}
.about-section p {
  font-size: 14px; color: var(--tx-1);
  line-height: 1.7;
}
.about-tags { display: flex; gap: 8px; margin-top: 12px; }
.about-spec-grid {
  display: grid; grid-template-columns: repeat(2, 1fr);
  gap: 8px; margin-top: 12px;
}
.spec-item {
  display: flex; gap: 8px; font-family: var(--font-display);
  font-size: 12px;
}
.spec-key { color: var(--tx-3); }
.spec-val { color: var(--accent); }

/* --- Theme Switcher --- */
.theme-switcher {
  display: flex; gap: 8px; margin-bottom: 16px; margin-top: 12px;
}
.theme-option {
  display: flex; align-items: center; gap: 8px;
  padding: 8px 14px; border: 1px solid var(--line-strong);
  background: transparent; cursor: pointer;
  font-family: var(--font-display); font-size: 12px;
  letter-spacing: .06em; color: var(--tx-2);
  transition: var(--transition);
}
.theme-option:hover { background: var(--accent-dim); }
.theme-option.active { border-color: var(--accent); color: #ffffff; }
.theme-dot {
  width: 14px; height: 14px; border-radius: 0;
  border: 1px solid rgba(255,255,255,.12);
}
.theme-name { font-weight: 500; }

/* ===== PRICING / 订阅计划 ===== */
.pricing-hero { text-align: center; padding: 48px 24px 32px; }
.pricing-hero h2 {
  font-family: var(--font-display); font-size: 24px; font-weight: 700;
  letter-spacing: .08em; color: var(--accent); margin-bottom: 8px;
}
.pricing-hero p {
  font-family: var(--font-body); font-size: 13px; color: var(--tx-2);
  letter-spacing: .04em; max-width: 480px; margin: 0 auto;
}
.tier-toggle {
  display: flex; justify-content: center; gap: 0;
  margin: 24px auto 0;
}
.tier-toggle button {
  font-family: var(--font-display); font-size: 12px; font-weight: 500;
  letter-spacing: .08em; padding: 10px 28px;
  border: 1px solid var(--line); background: transparent;
  color: var(--tx-2); cursor: pointer; transition: var(--transition);
}
.tier-toggle button.active {
  background: var(--accent); color: var(--bg-0); border-color: var(--accent);
}
.tier-toggle button:first-child { border-right: none; }
.pricing-grid {
  display: grid; grid-template-columns: repeat(4, 1fr);
  gap: 0; border: 1px solid var(--line); margin-top: 32px;
}
.pricing-card {
  background: var(--bg-1); border-right: 1px solid var(--line);
  padding: 32px 24px; position: relative; transition: var(--transition);
}
.pricing-card:last-child { border-right: none; }
.pricing-card:hover { background: var(--bg-2); }
.pricing-card.featured { background: var(--bg-2); }
.pricing-card.featured::before {
  content: "RECOMMENDED"; position: absolute; top: 0; left: 0; right: 0;
  font-family: var(--font-display); font-size: 9px; font-weight: 600;
  letter-spacing: .12em; color: var(--bg-0); background: var(--accent);
  text-align: center; padding: 6px 0;
}
.pricing-card .tier-name {
  font-family: var(--font-display); font-size: 11px; font-weight: 600;
  letter-spacing: .1em; color: var(--tx-3); margin-bottom: 8px;
}
.pricing-card .tier-label {
  font-family: var(--font-display); font-size: 16px; font-weight: 700;
  letter-spacing: .02em; color: var(--tx-1); margin-bottom: 4px;
}
.pricing-card .tier-desc {
  font-family: var(--font-body); font-size: 12px; color: var(--tx-2);
  letter-spacing: .02em; margin-bottom: 20px; line-height: 1.5;
}
.pricing-card .tier-price {
  font-family: var(--font-display); font-size: 24px; font-weight: 700;
  color: var(--tx-1); margin-bottom: 2px;
}
.pricing-card .tier-price .currency {
  font-size: 14px; font-weight: 500; vertical-align: top; margin-right: 2px;
}
.pricing-card .tier-price .period {
  font-size: 12px; font-weight: 400; color: var(--tx-3); margin-left: 4px;
}
.pricing-card .tier-unit {
  font-family: var(--font-display); font-size: 11px; color: var(--tx-3);
  letter-spacing: .04em; margin-bottom: 20px;
}
.pricing-card .tier-cta {
  display: block; width: 100%;
  font-family: var(--font-display); font-size: 12px; font-weight: 600;
  letter-spacing: .08em; padding: 10px 0;
  border: 1px solid var(--line); background: transparent;
  color: var(--tx-1); cursor: pointer; text-align: center;
  transition: var(--transition); margin-bottom: 20px;
}
.pricing-card .tier-cta:hover { background: var(--accent); color: var(--bg-0); border-color: var(--accent); }
.pricing-card.featured .tier-cta { background: var(--accent); color: var(--bg-0); border-color: var(--accent); }
.pricing-card.featured .tier-cta:hover { background: transparent; color: var(--tx-1); border-color: var(--accent); }
.pricing-card .feature-list { list-style: none; padding: 0; }
.pricing-card .feature-list li {
  font-family: var(--font-body); font-size: 12px; color: var(--tx-2);
  letter-spacing: .02em; padding: 5px 0;
  border-bottom: 1px solid var(--line-dash);
  display: flex; align-items: baseline; gap: 8px;
}
.pricing-card .feature-list li:last-child { border-bottom: none; }
.pricing-card .feature-list li .feat-key { font-weight: 500; color: var(--tx-1); min-width: 72px; }
.pricing-card .feature-list li .feat-val { color: var(--tx-2); }
.pricing-card .feature-list li .feat-val.limit { color: var(--tx-3); }
.pricing-card .feature-list li .feat-val.unlimited { color: var(--accent); }

/* Feature Matrix */
.matrix-section { margin-top: 40px; }
.matrix-section h3 {
  font-family: var(--font-display); font-size: 13px; font-weight: 600;
  letter-spacing: .08em; color: var(--tx-3); margin-bottom: 16px;
}
.matrix-table { width: 100%; border-collapse: collapse; font-family: var(--font-body); font-size: 12px; border: 1px solid var(--line); }
.matrix-table th {
  font-family: var(--font-display); font-size: 11px; font-weight: 600;
  letter-spacing: .08em; color: var(--tx-3); padding: 10px 12px;
  border-bottom: 1px solid var(--line-strong); text-align: left; background: var(--bg-1);
}
.matrix-table td {
  padding: 8px 12px; border-bottom: 1px solid var(--line); color: var(--tx-2);
}
.matrix-table td.cat {
  font-family: var(--font-display); font-size: 11px; font-weight: 600;
  letter-spacing: .06em; color: var(--tx-3); border-bottom: 1px solid var(--line-strong);
  padding-top: 14px; background: var(--bg-1);
}
.matrix-table td.row-label { color: var(--tx-1); font-weight: 500; }
.matrix-table td.check { color: var(--accent); text-align: center; font-weight: 700; }
.matrix-table td.no { color: var(--tx-3); text-align: center; }
.matrix-table td.limit-val { color: var(--tx-3); text-align: center; }

/* ADE Flow */
.ade-section { margin-top: 40px; }
.ade-section h3 {
  font-family: var(--font-display); font-size: 13px; font-weight: 600;
  letter-spacing: .08em; color: var(--tx-3); margin-bottom: 16px;
}
.ade-flow {
  display: grid; grid-template-columns: 1fr auto 1fr auto 1fr;
  align-items: center; border: 1px solid var(--line);
}
.ade-block {
  background: var(--bg-1); padding: 24px 20px; text-align: center;
  border-right: 1px solid var(--line);
}
.ade-block:last-child { border-right: none; }
.ade-block .ade-letter {
  font-family: var(--font-display); font-size: 28px; font-weight: 700;
  color: var(--accent); margin-bottom: 4px;
}
.ade-block .ade-name {
  font-family: var(--font-display); font-size: 11px; font-weight: 600;
  letter-spacing: .08em; color: var(--tx-3); margin-bottom: 8px;
}
.ade-block .ade-role { font-size: 12px; color: var(--tx-2); line-height: 1.5; }
.ade-arrow { font-family: var(--font-display); font-size: 18px; color: var(--tx-3); padding: 0 8px; }

/* FAQ */
.faq-section { margin-top: 40px; }
.faq-section h3 {
  font-family: var(--font-display); font-size: 13px; font-weight: 600;
  letter-spacing: .08em; color: var(--tx-3); margin-bottom: 16px;
}
.faq-item { border-bottom: 1px solid var(--line); padding: 14px 0; }
.faq-item .faq-q {
  font-family: var(--font-display); font-size: 13px; font-weight: 500;
  color: var(--tx-1); letter-spacing: .02em; cursor: pointer;
  display: flex; justify-content: space-between; align-items: center;
}
.faq-item .faq-q .faq-toggle { font-size: 11px; color: var(--tx-3); transition: var(--transition); }
.faq-item.open .faq-q .faq-toggle { transform: rotate(45deg); }
.faq-item .faq-a {
  font-family: var(--font-body); font-size: 12px; color: var(--tx-2);
  line-height: 1.8; max-height: 0; overflow: hidden; transition: max-height .3s ease;
}
.faq-item.open .faq-a { max-height: 300px; margin-top: 10px; }

/* --- Tier Badge (system enhancement) --- */
.tier-badge {
  font-family: var(--font-display); font-size: 9px; font-weight: 700;
  letter-spacing: .1em; padding: 2px 8px;
  border: 1px solid var(--line-strong); text-transform: uppercase;
}
.tier-badge.free { color: var(--tx-3); }
.tier-badge.pro { color: var(--accent); border-color: var(--accent); }
.tier-badge.team { color: var(--warn); border-color: var(--warn); }
.tier-badge.api { color: var(--tx-2); }
.feature-lock {
  position: relative; opacity: .5; cursor: not-allowed;
}
.feature-lock::after {
  content: 'PRO'; position: absolute; top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  font-family: var(--font-display); font-size: 10px; font-weight: 700;
  letter-spacing: .1em; color: var(--accent); background: var(--bg-0);
  padding: 2px 6px; border: 1px solid var(--accent);
}
.usage-limit-bar {
  display: flex; align-items: center; gap: 8px;
  font-family: var(--font-display); font-size: 10px; color: var(--tx-3);
  letter-spacing: .04em; margin-top: 4px;
}
.usage-limit-fill {
  height: 3px; background: var(--bg-3); width: 60px; overflow: hidden;
}
.usage-limit-fill .used { height: 100%; background: var(--accent); }
.usage-limit-fill .over { height: 100%; background: var(--err); }

/* --- Current Tier Indicator --- */
.current-tier-indicator {
  display: flex; align-items: center; gap: 6px;
  padding: 4px 10px; border: 1px solid var(--line-strong);
  background: var(--accent-dim);
  font-family: var(--font-display); font-size: 10px; font-weight: 600;
  letter-spacing: .1em; color: var(--accent);
}

@media (max-width: 768px) {
  .pricing-grid { grid-template-columns: 1fr; }
  .pricing-card { border-right: none; border-bottom: 1px solid var(--line); }
  .pricing-card:last-child { border-bottom: none; }
  .ade-flow { grid-template-columns: 1fr; }
  .ade-arrow { display: none; }
  .ade-block { border-right: none; border-bottom: 1px solid var(--line); }
}

@media (max-width: 768px) {
  .pipeline-bar { flex-wrap: wrap; gap: 8px; }
  .pipeline-connector { display: none; }
  .form-grid { grid-template-columns: 1fr; }
  .upload-zone { padding: 30px 20px; }
  .blog-card { grid-template-columns: 1fr; }
  .about-spec-grid { grid-template-columns: 1fr; }
}