/* ================================================================
   styles.css — Math Q&A Search — Elegant Dark Theme
   Redesigned with dark mode, glass effects, and AI panels
   ================================================================ */

/* ── Variables ── */
:root,
[data-theme="light"] {
  --bg: #fafaf9;
  --surface: #ffffff;
  --surface-2: #f5f5f4;
  --surface-3: #e7e5e4;
  --border: #d6d3d1;
  --border-2: #a8a29e;
  --text: #1c1917;
  --text-2: #44403c;
  --text-3: #78716c;
  --text-4: #a8a29e;
  --accent: #0d9488;
  --accent-2: #0f766e;
  --accent-bg: rgba(13, 148, 136, 0.08);
  --accent-border: rgba(13, 148, 136, 0.25);
  --ai-glow: rgba(13, 148, 136, 0.12);
  --ai-border: rgba(13, 148, 136, 0.3);
  --ai-bg: rgba(13, 148, 136, 0.04);
  --error: #dc2626;
  --warning-bg: #fffbeb;
  --warning-border: #fbbf24;
  --warning-text: #92400e;
  --code-bg: #f5f5f4;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 12px 32px rgba(0,0,0,0.12);
  --radius: 8px;
  --radius-sm: 4px;
  --radius-lg: 12px;
  --transition: 180ms cubic-bezier(0.16, 1, 0.3, 1);
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
}

[data-theme="dark"] {
  --bg: #0c0a09;
  --surface: #1c1917;
  --surface-2: #292524;
  --surface-3: #44403c;
  --border: #44403c;
  --border-2: #57534e;
  --text: #e7e5e4;
  --text-2: #a8a29e;
  --text-3: #78716c;
  --text-4: #57534e;
  --accent: #2dd4bf;
  --accent-2: #14b8a6;
  --accent-bg: rgba(45, 212, 191, 0.08);
  --accent-border: rgba(45, 212, 191, 0.25);
  --ai-glow: rgba(45, 212, 191, 0.1);
  --ai-border: rgba(45, 212, 191, 0.3);
  --ai-bg: rgba(45, 212, 191, 0.04);
  --error: #f87171;
  --warning-bg: #1c1917;
  --warning-border: #92400e;
  --warning-text: #fbbf24;
  --code-bg: #292524;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.4);
  --shadow-lg: 0 12px 32px rgba(0,0,0,0.5);
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  font-size: 14px;
  line-height: 1.6;
  min-height: 100dvh;
}

::selection {
  background: var(--accent);
  color: white;
}

/* ===================== HEADER ===================== */
header {
  width: 100%;
  background: var(--surface);
  padding: 32px 20px 28px;
  text-align: center;
  border-bottom: 1px solid var(--border);
  position: relative;
}

header h1 {
  font-size: 28px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.5px;
  margin: 0;
}

header p {
  margin-top: 6px;
  font-size: 13px;
  color: var(--text-3);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* Theme toggle in header */
.theme-toggle {
  position: absolute;
  top: 16px;
  right: 20px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-3);
  transition: all var(--transition);
}

.theme-toggle:hover {
  background: var(--surface-3);
  color: var(--text);
}

/* ===================== MODE TOGGLE ===================== */
.mode-toggle {
  max-width: 720px;
  width: 100%;
  margin: 0 auto;
  padding: 20px 20px 0;
  display: flex;
  justify-content: center;
  gap: 4px;
}

.mode-btn {
  padding: 9px 20px;
  font-size: 13px;
  font-weight: 500;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-2);
  cursor: pointer;
  font-family: var(--font-body);
  border-radius: var(--radius);
  transition: all var(--transition);
}

.mode-btn:first-child { border-radius: var(--radius) 0 0 var(--radius); }
.mode-btn:last-child  { border-radius: 0 var(--radius) var(--radius) 0; }

.mode-btn:hover { background: var(--surface-2); color: var(--text); }

.mode-btn.active {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}

/* ===================== SEARCH BOX ===================== */
.search-container {
  width: 100%;
  max-width: 720px;
  margin: 16px auto 0;
  padding: 0 20px;
}

.search-box {
  display: flex;
  border: 2px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--surface);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition);
}

.search-box:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--ai-glow);
}

.search-box input {
  flex: 1;
  border: none;
  padding: 12px 16px;
  font-size: 15px;
  outline: none;
  background: transparent;
  color: var(--text);
  min-width: 0;
  font-family: var(--font-body);
}

.search-box input::placeholder { color: var(--text-4); }

.search-box button {
  background: var(--accent);
  border: none;
  padding: 12px 20px;
  cursor: pointer;
  font-size: 14px;
  color: white;
  font-weight: 600;
  font-family: var(--font-body);
  flex-shrink: 0;
  transition: all var(--transition);
}

.search-box button:hover { background: var(--accent-2); }

/* ===================== LATEX PANEL ===================== */
.latex-panel {
  width: 100%;
  max-width: 720px;
  margin: 16px auto 0;
  padding: 0 20px;
  display: none;
}

.latex-panel.visible { display: block; }

.latex-card {
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--surface);
  box-shadow: var(--shadow-sm);
}

.latex-input-area textarea {
  width: 100%;
  min-height: 80px;
  border: none;
  outline: none;
  padding: 12px 14px;
  font-size: 14px;
  font-family: var(--font-mono);
  resize: vertical;
  color: var(--text);
  background: transparent;
}

.latex-preview-bar {
  padding: 6px 14px;
  background: var(--surface-2);
  border-top: 1px solid var(--border);
  font-size: 10px;
  color: var(--text-3);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
}

.latex-preview {
  padding: 14px;
  background: var(--surface);
  border-top: 1px solid var(--border);
  min-height: 44px;
  overflow-x: auto;
  font-size: 18px;
}

.latex-preview .placeholder-text {
  color: var(--text-4);
  font-style: italic;
  font-size: 13px;
}

.latex-search-row {
  display: flex;
  border-top: 1px solid var(--border);
}

.latex-search-row input {
  flex: 1;
  border: none;
  outline: none;
  padding: 10px 14px;
  font-size: 14px;
  font-family: var(--font-body);
  color: var(--text);
  background: transparent;
  min-width: 0;
}

.latex-search-row input::placeholder { color: var(--text-4); }

.latex-search-row button {
  border: none;
  border-left: 1px solid var(--border);
  padding: 10px 20px;
  background: var(--accent);
  cursor: pointer;
  font-size: 14px;
  color: white;
  font-weight: 600;
  font-family: var(--font-body);
  flex-shrink: 0;
  transition: all var(--transition);
}

.latex-search-row button:hover { background: var(--accent-2); }


/* ===================== AI ACTION BAR ===================== */
.ai-action-bar {
  max-width: 720px;
  width: 100%;
  margin: 10px auto 0;
  padding: 0 20px;
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}

.ai-bar-btn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 6px 12px;
  font-size: 12px;
  font-weight: 500;
  color: var(--accent);
  background: var(--ai-bg);
  border: 1px solid var(--ai-border);
  border-radius: var(--radius);
  cursor: pointer;
  font-family: var(--font-body);
  transition: all var(--transition);
}

.ai-bar-btn:hover {
  background: var(--accent-bg);
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--ai-glow);
}

.ai-bar-btn:disabled {
  opacity: 0.4;
  cursor: default;
}

.ai-bar-btn svg {
  flex-shrink: 0;
}

.ai-bar-btn.loading {
  pointer-events: none;
}

.ai-bar-btn.loading::after {
  content: '';
  width: 12px;
  height: 12px;
  border: 2px solid var(--ai-border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  margin-left: 4px;
}

/* AI Toggle switch */
.ai-toggle-wrap {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-left: auto;
}

.ai-toggle {
  position: relative;
  width: 32px;
  height: 18px;
  display: inline-block;
}

.ai-toggle input { opacity: 0; width: 0; height: 0; }

.ai-toggle-slider {
  position: absolute;
  inset: 0;
  background: var(--surface-3);
  border-radius: 9px;
  cursor: pointer;
  transition: all var(--transition);
}

.ai-toggle-slider::before {
  content: '';
  position: absolute;
  width: 14px;
  height: 14px;
  left: 2px;
  top: 2px;
  background: white;
  border-radius: 50%;
  transition: all var(--transition);
}

.ai-toggle input:checked + .ai-toggle-slider {
  background: var(--accent);
}

.ai-toggle input:checked + .ai-toggle-slider::before {
  transform: translateX(14px);
}

.ai-toggle-label {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-3);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* ===================== SORT TOOLBAR ===================== */
.sort-toolbar {
  max-width: 720px;
  width: 100%;
  margin: 10px auto 0;
  padding: 0 20px;
}

.sort-toolbar-row {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.sort-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-3);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.sort-pills {
  display: flex;
  gap: 3px;
  flex-wrap: wrap;
  align-items: center;
}

.sort-pill {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 5px 10px;
  font-size: 12px;
  font-weight: 500;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  color: var(--text-2);
  font-family: var(--font-body);
  transition: all var(--transition);
  white-space: nowrap;
}

.sort-pill:hover {
  background: var(--surface-2);
  border-color: var(--border-2);
  color: var(--text);
}

.sort-pill.active {
  background: var(--accent-bg);
  border-color: var(--accent-border);
  color: var(--accent);
  font-weight: 600;
}

.sort-pill-icon { font-size: 12px; }
.sort-pill-text { font-size: 11px; }

.sort-count {
  margin-left: auto;
  font-size: 12px;
  color: var(--text-3);
  font-weight: 500;
}

/* Sort More Dropdown */
.sort-more-wrap { position: relative; }

.sort-more-dropdown {
  display: none;
  position: absolute;
  top: calc(100% + 4px);
  right: 0;
  min-width: 220px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
  z-index: 100;
  overflow: hidden;
}

.sort-more-dropdown.open { display: block; }

.sort-more-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  font-size: 12px;
  color: var(--text-2);
  cursor: pointer;
  transition: background var(--transition);
}

.sort-more-item:hover { background: var(--surface-2); }
.sort-more-item.active { color: var(--accent); font-weight: 600; }

.sort-more-desc {
  margin-left: auto;
  font-size: 10px;
  color: var(--text-4);
}

/* ===================== FILTERS ===================== */
.filters {
  max-width: 720px;
  width: 100%;
  margin: 8px auto 0;
  padding: 0 20px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
  font-size: 12px;
}

.filters label { color: var(--text-3); font-weight: 600; }

.filters select {
  padding: 5px 10px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 12px;
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  font-family: var(--font-body);
  transition: all var(--transition);
}

.filters select:focus { outline: none; border-color: var(--accent); }

/* ===================== STATUS / LOADER ===================== */
.status {
  text-align: center;
  margin: 16px auto 8px;
  font-size: 13px;
  color: var(--text-3);
  max-width: 720px;
  width: 100%;
}

.loader {
  width: 24px;
  height: 24px;
  border: 2px solid var(--surface-3);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  margin: 16px auto;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ── Deep Search Timer ── */
.deep-timer {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 10px auto;
  max-width: 400px;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 13px;
  color: var(--text-2);
  background: var(--surface);
}

.deep-timer .dt-clock {
  font-size: 15px;
  font-weight: 700;
  min-width: 46px;
  text-align: center;
  font-family: var(--font-mono);
  color: var(--accent);
}

.deep-timer .dt-bar-wrap {
  flex: 1;
  height: 3px;
  background: var(--surface-3);
  border-radius: 2px;
  overflow: hidden;
}

.deep-timer .dt-bar {
  height: 100%;
  background: var(--accent);
  transition: width 0.95s linear;
  border-radius: 2px;
}

.deep-timer .dt-wave { font-size: 12px; color: var(--text-3); }
.deep-timer.done { border-color: var(--accent); }

/* ===================== RESULTS ===================== */
.results {
  width: 100%;
  max-width: 720px;
  padding: 0 20px 40px;
  margin: 8px auto 0;
}

.result-card,
.az-result-card {
  background: var(--surface);
  padding: 16px;
  margin-bottom: 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: all var(--transition);
}

.result-card:hover,
.az-result-card:hover {
  border-color: var(--border-2);
  box-shadow: var(--shadow-sm);
}

.az-result-card {
  border-left: 3px solid var(--accent);
}

.result-card h3,
.az-result-card h3 {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 8px;
  line-height: 1.35;
}

.result-card h3 a,
.az-result-card h3 a {
  color: var(--text);
  text-decoration: none;
  transition: color var(--transition);
}

.result-card h3 a:hover,
.az-result-card h3 a:hover { color: var(--accent); }

.result-card h3 a:visited,
.az-result-card h3 a:visited { color: var(--text-2); }

/* Badges */
.sim-badge {
  display: inline-block;
  font-size: 10px;
  font-weight: 600;
  padding: 2px 6px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  margin-right: 4px;
  vertical-align: middle;
}

.sim-high { background: var(--accent-bg); color: var(--accent); border-color: var(--accent-border); }
.sim-med  { background: var(--surface-2); color: var(--text-2); }
.sim-low  { background: var(--surface-3); color: var(--text-3); }

.result-snippet {
  font-size: 13px;
  color: var(--text-2);
  margin-bottom: 8px;
  line-height: 1.5;
  max-height: 100px;
  overflow: hidden;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 12px;
  color: var(--text-3);
}

.meta span { display: flex; align-items: center; gap: 4px; }

.tag {
  background: var(--surface-2);
  color: var(--text-3);
  padding: 2px 8px;
  font-size: 11px;
  cursor: default;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}

.tag:hover { color: var(--accent); background: var(--accent-bg); }
.tags { margin-top: 6px; display: flex; flex-wrap: wrap; gap: 4px; }

.accepted { color: var(--accent); font-size: 12px; font-weight: 600; }

.score-badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  padding: 2px 7px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-2);
}

/* ===================== AI PANELS ===================== */

/* AI Badge */
.ai-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 10px;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* AI Summary */
.ai-summary-panel {
  margin: 10px 0;
  padding: 12px 14px;
  background: var(--ai-bg);
  border: 1px solid var(--ai-border);
  border-radius: var(--radius);
  border-left: 3px solid var(--accent);
}

.ai-summary-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
}

.ai-summary-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-2);
}

.ai-summary-body {
  font-size: 13px;
  color: var(--text);
  line-height: 1.6;
}

.ai-summary-body code {
  background: var(--code-bg);
  padding: 1px 4px;
  border-radius: 3px;
  font-family: var(--font-mono);
  font-size: 12px;
}

/* AI Action buttons on results */
.ai-action-btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  font-size: 11px;
  font-weight: 500;
  color: var(--accent);
  background: transparent;
  border: 1px solid var(--ai-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-family: var(--font-body);
  transition: all var(--transition);
  margin-top: 6px;
}

.ai-action-btn:hover {
  background: var(--ai-bg);
  border-color: var(--accent);
}

.ai-action-btn.loading::after {
  content: '';
  width: 10px;
  height: 10px;
  border: 1.5px solid var(--ai-border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

/* AI Quality Check */
.ai-quality-panel {
  max-width: 720px;
  width: 100%;
  margin: 8px auto;
  padding: 12px 14px;
  background: var(--ai-bg);
  border: 1px solid var(--ai-border);
  border-radius: var(--radius);
}

.qc-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 6px;
}

.qc-score {
  font-size: 16px;
  font-weight: 700;
  color: var(--accent);
}

.qc-high .qc-score { color: var(--accent); }
.qc-mid .qc-score { color: var(--warning-text); }
.qc-low .qc-score { color: var(--error); }

.qc-meter {
  height: 3px;
  background: var(--surface-3);
  border-radius: 2px;
  overflow: hidden;
  margin-bottom: 8px;
}

.qc-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  transition: width 0.5s ease;
}

.qc-high .qc-fill { background: var(--accent); }
.qc-mid .qc-fill { background: var(--warning-border); }
.qc-low .qc-fill { background: var(--error); }

.qc-assessment { font-size: 13px; color: var(--text-2); margin-bottom: 6px; }
.qc-best { font-size: 12px; color: var(--text-3); margin-bottom: 4px; }
.qc-sort-tip { font-size: 12px; color: var(--text-3); margin-bottom: 6px; }

.qc-refined, .qc-missing { display: flex; flex-wrap: wrap; gap: 4px; align-items: center; margin-top: 6px; }
.qc-refined-label, .qc-missing-label { font-size: 11px; font-weight: 600; color: var(--text-3); }

.qc-refined-chip {
  padding: 3px 10px;
  font-size: 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--accent);
  cursor: pointer;
  transition: all var(--transition);
}

.qc-refined-chip:hover {
  background: var(--accent-bg);
  border-color: var(--accent);
}

.qc-missing-tag {
  padding: 2px 8px;
  font-size: 11px;
  background: var(--surface-2);
  border-radius: var(--radius-sm);
  color: var(--text-3);
}

/* AI Suggestions */
.ai-suggestions-panel {
  max-width: 720px;
  width: 100%;
  margin: 8px auto;
  padding: 12px 14px;
  background: var(--ai-bg);
  border: 1px solid var(--ai-border);
  border-radius: var(--radius);
}

.ai-sug-header { margin-bottom: 8px; }

.ai-sug-list { display: flex; flex-direction: column; gap: 4px; }

.ai-sug-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition);
}

.ai-sug-item:hover {
  border-color: var(--accent);
  background: var(--accent-bg);
}

.ai-sug-query { font-size: 13px; font-weight: 500; color: var(--text); flex: 1; }
.ai-sug-reason { font-size: 11px; color: var(--text-3); flex: 1; }
.ai-sug-diff {
  font-size: 10px;
  font-weight: 600;
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
}

.sug-basic .ai-sug-diff { background: var(--accent-bg); color: var(--accent); }
.sug-mid .ai-sug-diff { background: var(--warning-bg); color: var(--warning-text); border: 1px solid var(--warning-border); }
.sug-adv .ai-sug-diff { background: rgba(168, 85, 247, 0.1); color: #a855f7; }

/* Formula Explanation */
.ai-explain-panel {
  margin: 10px 0;
  padding: 12px 14px;
  background: var(--ai-bg);
  border: 1px solid var(--ai-border);
  border-radius: var(--radius);
}

.ai-explain-header { margin-bottom: 8px; }
.ai-explain-body { font-size: 13px; color: var(--text); line-height: 1.6; }

/* Refresh Analysis */
.ai-refresh-panel {
  max-width: 720px;
  width: 100%;
  margin: 8px auto;
  padding: 12px 14px;
  background: var(--ai-bg);
  border: 1px solid var(--ai-border);
  border-radius: var(--radius);
}

.refresh-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.refresh-coverage {
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
}

.refresh-missing, .refresh-alts, .refresh-tags, .refresh-tip {
  font-size: 12px;
  color: var(--text-2);
  margin-top: 6px;
  line-height: 1.5;
}

.refresh-alt-chip {
  display: inline-block;
  padding: 3px 10px;
  font-size: 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--accent);
  cursor: pointer;
  margin: 2px 3px;
  transition: all var(--transition);
}

.refresh-alt-chip:hover { background: var(--accent-bg); border-color: var(--accent); }

.refresh-tag-chip {
  display: inline-block;
  padding: 2px 8px;
  font-size: 11px;
  background: var(--surface-2);
  border-radius: var(--radius-sm);
  color: var(--text-3);
  margin: 2px 3px;
}

.refresh-tip {
  padding: 6px 10px;
  background: var(--warning-bg);
  border: 1px solid var(--warning-border);
  border-radius: var(--radius-sm);
  color: var(--warning-text);
  font-size: 12px;
}

/* ===================== PAGINATION ===================== */
.pagination {
  text-align: center;
  margin-top: 16px;
  max-width: 720px;
  width: 100%;
  margin-left: auto;
  margin-right: auto;
}

.pagination button {
  padding: 8px 16px;
  margin: 0 4px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  font-size: 13px;
  cursor: pointer;
  font-family: var(--font-body);
  color: var(--text);
  transition: all var(--transition);
}

.pagination button:disabled { opacity: 0.3; cursor: default; }
.pagination button:not(:disabled):hover { background: var(--surface-2); border-color: var(--accent); }

/* ===================== FOOTER ===================== */
footer {
  text-align: center;
  margin-top: 40px;
  padding: 24px 20px;
  color: var(--text-3);
  font-size: 12px;
  border-top: 1px solid var(--border);
  background: var(--surface);
}

footer a { color: var(--accent); text-decoration: none; }
footer a:hover { text-decoration: underline; }

/* ===================== SOURCE BADGES ===================== */
.source-badge {
  display: inline-block;
  font-size: 9px;
  font-weight: 600;
  padding: 2px 6px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  margin-right: 3px;
  vertical-align: middle;
  text-transform: uppercase;
  letter-spacing: 0.3px;
  color: var(--text-3);
  background: var(--surface-2);
}

.source-az        { color: var(--accent); border-color: var(--accent-border); }
.source-mathoverflow { color: #9333ea; }
.source-google    { color: #2563eb; }

.relevance-badge {
  display: inline-block;
  font-size: 10px;
  font-weight: 600;
  padding: 2px 7px;
  border-radius: var(--radius-sm);
  margin-right: 3px;
  vertical-align: middle;
}

.relevance-high { background: var(--accent-bg); color: var(--accent); }
.relevance-mid  { background: var(--surface-2); color: var(--text-2); }
.relevance-low  { background: var(--surface-3); color: var(--text-3); }

/* Keep remaining source badge classes */
.source-answer, .source-multi, .source-related, .source-linked,
.source-synonym, .source-tagged, .source-decompose, .source-phrase,
.source-hot, .source-rewrite, .source-intent, .source-bridge,
.source-fallback, .source-dup { }

/* ===================== SEARCH ANALYTICS ===================== */
.search-analytics {
  max-width: 720px;
  width: 100%;
  margin: 6px auto 4px;
  padding: 0 20px;
}

.analytics-toggle {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 12px;
  color: var(--text-3);
  font-family: var(--font-body);
  transition: all var(--transition);
}

.analytics-toggle:hover { background: var(--surface-2); }
.analytics-summary { margin-left: auto; font-weight: 600; color: var(--accent); }

.analytics-body {
  display: none;
  padding: 10px 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-top: none;
  border-radius: 0 0 var(--radius) var(--radius);
  font-size: 11px;
  color: var(--text-3);
}

.search-analytics.expanded .analytics-body { display: block; }
.analytics-row { margin-bottom: 4px; }

.analytics-chip {
  display: inline-block;
  background: var(--surface-2);
  color: var(--text-2);
  padding: 2px 6px;
  font-size: 10px;
  margin-right: 3px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.tag-chip { background: var(--surface-2); color: var(--text-2); border: 1px solid var(--border); }

/* ===================== SEARCH HISTORY ===================== */
.history-bar {
  max-width: 720px;
  width: 100%;
  margin: 8px auto 0;
  padding: 0 20px;
  display: none;
  font-size: 12px;
}

.history-bar.visible { display: block; }

.history-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text-4);
  margin-bottom: 6px;
  font-weight: 500;
}

.history-clear {
  background: none;
  border: none;
  color: var(--text-4);
  cursor: pointer;
  font-size: 16px;
  font-family: var(--font-body);
  transition: color var(--transition);
}

.history-clear:hover { color: var(--error); }

.history-chips { display: flex; flex-wrap: wrap; gap: 4px; }

.history-chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 12px;
  cursor: pointer;
  max-width: 260px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  transition: all var(--transition);
}

.history-chip:hover { border-color: var(--accent); background: var(--accent-bg); }

.history-chip .chip-mode {
  font-size: 10px;
  font-weight: 600;
  opacity: 0.6;
  text-transform: uppercase;
}

/* ===================== GOOGLE FALLBACK ===================== */
.google-fallback {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin: 16px 0 8px;
  padding: 10px 14px;
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  font-size: 13px;
  color: var(--text-3);
}

.google-fallback a { color: var(--accent); font-weight: 600; text-decoration: none; }
.google-fallback a:hover { text-decoration: underline; }
.google-inline-link { color: var(--accent); font-weight: 600; margin-left: 6px; text-decoration: none; }

/* ===================== HELPERS ===================== */
.hidden { display: none !important; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
button { font-family: var(--font-body); }

/* ===================== TAG WIKI PANEL ===================== */
.tag-wiki-panel {
  max-width: 720px;
  width: 100%;
  margin: 6px auto 8px;
  padding: 0 20px;
}

.tag-wiki-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius) var(--radius) 0 0;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-2);
  cursor: pointer;
  transition: all var(--transition);
}

.tag-wiki-header:hover { background: var(--surface-2); }
.tag-wiki-toggle { font-size: 11px; transition: transform 0.2s; }
.tag-wiki-panel.expanded .tag-wiki-toggle { transform: rotate(180deg); }

.tag-wiki-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
  border: 1px solid var(--border);
  border-top: none;
  border-radius: 0 0 var(--radius) var(--radius);
  background: var(--surface);
}

.tag-wiki-panel.expanded .tag-wiki-body { max-height: 500px; overflow-y: auto; }

.tag-wiki-card {
  padding: 8px 12px;
  border-bottom: 1px solid var(--border);
  font-size: 13px;
  line-height: 1.5;
}

.tag-wiki-card:last-child { border-bottom: none; }

.tag-wiki-tag {
  display: inline-block;
  background: var(--surface-2);
  color: var(--text-2);
  font-size: 11px;
  font-weight: 600;
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  margin-right: 6px;
}

.tag-wiki-excerpt { color: var(--text-2); }

/* ===================== AUTOCORRECT BANNER ===================== */
.autocorrect-banner {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  background: var(--warning-bg);
  border: 1px solid var(--warning-border);
  border-radius: var(--radius);
  font-size: 12px;
  color: var(--warning-text);
  margin-bottom: 8px;
}

.autocorrect-icon { font-size: 14px; flex-shrink: 0; }
.autocorrect-banner strong { color: var(--text); }
.autocorrect-original { color: var(--text-4); font-size: 11px; }
.autocorrect-original s { color: var(--error); text-decoration: line-through; }

.autocorrect-undo {
  margin-left: auto;
  padding: 3px 8px;
  background: transparent;
  border: 1px solid var(--warning-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 11px;
  color: var(--warning-text);
  font-family: var(--font-body);
  transition: all var(--transition);
}

.autocorrect-undo:hover { background: var(--warning-border); color: white; }

/* ===================== Q&A BODY ===================== */
.qa-body {
  margin: 8px 0;
  padding: 10px 0;
  font-size: 13px;
}

.qa-body-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-2);
  margin-bottom: 6px;
}

.qa-body-content { word-wrap: break-word; overflow: hidden; color: var(--text); }

.qa-body-content.collapsed {
  max-height: 180px;
  overflow: hidden;
  position: relative;
}

.qa-body-content.collapsed::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 40px;
  background: linear-gradient(transparent, var(--surface));
  pointer-events: none;
}

.qa-body-content img { max-width: 100%; height: auto; border-radius: var(--radius-sm); }

.qa-body-content pre {
  background: var(--code-bg);
  padding: 10px;
  overflow-x: auto;
  font-size: 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
}

.qa-body-content blockquote {
  border-left: 3px solid var(--accent);
  margin: 8px 0;
  padding: 6px 12px;
  background: var(--surface-2);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.qa-toggle {
  margin-top: 6px;
  padding: 5px 10px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 12px;
  color: var(--text-3);
  font-family: var(--font-body);
  transition: all var(--transition);
}

.qa-toggle:hover { background: var(--surface-2); color: var(--text); }

/* ===================== ANSWERS ===================== */
.answers-section {
  margin: 8px 0;
  border-bottom: 1px solid var(--border);
}

.answers-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 0;
  cursor: pointer;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-2);
  user-select: none;
  transition: color var(--transition);
}

.answers-header:hover { color: var(--accent); }
.answers-toggle-icon { font-size: 12px; }

.answers-list { transition: max-height 0.25s ease; }
.answers-list.collapsed { max-height: 0; overflow: hidden; }

.answer-card {
  padding: 10px 0;
  border-top: 1px solid var(--border);
  font-size: 13px;
}

.answer-card.answer-accepted {
  background: var(--accent-bg);
  border-left: 3px solid var(--accent);
  padding-left: 12px;
  border-radius: var(--radius-sm);
  margin: 4px 0;
}

.answer-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 6px;
  flex-wrap: wrap;
  font-size: 12px;
  color: var(--text-3);
}

.accepted-answer-badge {
  background: var(--accent);
  color: white;
  padding: 2px 8px;
  font-weight: 600;
  font-size: 10px;
  border-radius: var(--radius-sm);
}

.answer-score  { font-weight: 600; color: var(--text-2); }
.answer-author { color: var(--text-3); }
.answer-date   { color: var(--text-4); }

.answer-card .qa-body-content.collapsed::after { background: linear-gradient(transparent, var(--surface)); }
.answer-card.answer-accepted .qa-body-content.collapsed::after { background: linear-gradient(transparent, var(--accent-bg)); }

/* ===================== SMART SNIPPET ===================== */
.smart-snippet {
  padding: 10px 14px;
  margin: 8px 0;
  background: var(--ai-bg);
  border: 1px solid var(--ai-border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  font-size: 13px;
  line-height: 1.5;
  color: var(--text);
}

.snippet-label {
  font-weight: 600;
  font-size: 10px;
  color: var(--accent);
  margin-right: 4px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* ===================== CONFIDENCE BAR ===================== */
.confidence-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  max-width: 720px;
  width: 100%;
  margin: 4px auto;
  padding: 4px 20px;
  font-size: 12px;
}

.confidence-bar > * { flex-shrink: 0; }
.confidence-icon { font-size: 13px; }
.confidence-text { color: var(--text-3); }
.confidence-score { font-weight: 600; min-width: 28px; text-align: right; color: var(--accent); }

.confidence-meter {
  flex: 1;
  height: 3px;
  background: var(--surface-3);
  border-radius: 2px;
  overflow: hidden;
  min-width: 40px;
}

.confidence-fill { height: 100%; background: var(--accent); transition: width 0.5s ease; border-radius: 2px; }

.confidence-high .confidence-score  { color: var(--accent); }
.confidence-medium .confidence-score { color: var(--warning-text); }
.confidence-low .confidence-score   { color: var(--error); }

/* ===================== SEARCH SUGGESTIONS ===================== */
.search-suggestions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  max-width: 720px;
  width: 100%;
  margin: 6px auto 4px;
  padding: 0 20px;
  font-size: 12px;
}

.suggestions-label { font-weight: 600; color: var(--text-3); }

.suggestion-chip {
  display: inline-block;
  padding: 4px 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 12px;
  color: var(--text-2);
  cursor: pointer;
  transition: all var(--transition);
}

.suggestion-chip:hover { background: var(--accent-bg); border-color: var(--accent); color: var(--accent); }

/* ===================== QUALITY BADGE ===================== */
.quality-badge {
  display: inline-block;
  font-size: 10px;
  font-weight: 600;
  padding: 2px 6px;
  border-radius: var(--radius-sm);
}

.quality-high { background: var(--accent-bg); color: var(--accent); }
.quality-mid  { background: var(--surface-2); color: var(--text-2); }
.quality-low  { background: var(--surface-3); color: var(--text-3); }

/* ===================== SEARCH TIPS ===================== */
.search-tips {
  max-width: 720px;
  width: 100%;
  margin: 10px auto 0;
  padding: 0 20px;
}

.search-tips-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.search-tips-header {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 10px 14px;
  cursor: pointer;
  font-weight: 600;
  font-size: 13px;
  user-select: none;
  color: var(--text-2);
  transition: all var(--transition);
}

.search-tips-header:hover { background: var(--surface-2); }
.search-tips-icon { font-size: 14px; }
.search-tips-toggle { margin-left: auto; font-size: 11px; transition: transform 0.25s; }
.search-tips.expanded .search-tips-toggle { transform: rotate(180deg); }

.search-tips-body { max-height: 0; overflow: hidden; transition: max-height 0.35s ease; }
.search-tips.expanded .search-tips-body { max-height: 1000px; overflow-y: auto; }

.search-tips-content {
  padding: 14px;
  font-size: 13px;
  color: var(--text-2);
  line-height: 1.6;
}

.equiv-table {
  width: 100%;
  font-size: 12px;
  border-collapse: collapse;
  margin: 8px 0;
}

.equiv-table thead { background: var(--surface-2); }

.equiv-table td, .equiv-table th {
  padding: 5px 8px;
  border: 1px solid var(--border);
  text-align: left;
}

.equiv-table tr:hover td { background: var(--surface-2); }

.equiv-code {
  background: var(--code-bg);
  padding: 2px 5px;
  font-family: var(--font-mono);
  font-size: 11px;
  border-radius: 3px;
}

.equiv-arrow { font-weight: 700; color: var(--accent); }

.tips-list { list-style: none; margin: 6px 0; }

.tips-list li {
  padding: 3px 0 3px 20px;
  font-size: 13px;
  position: relative;
}

.tips-list li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 700;
}

.tips-section-title {
  font-weight: 600;
  margin: 12px 0 6px;
  font-size: 13px;
  color: var(--text);
}

/* ===================== TAG AUTOCOMPLETE ===================== */
.tag-autocomplete {
  max-width: 720px;
  width: 100%;
  margin: 8px auto 0;
  padding: 0 20px;
  display: none;
}

.tag-selected-chips { display: flex; flex-wrap: wrap; gap: 4px; margin-bottom: 6px; }

.tag-selected-chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 8px;
  background: var(--accent-bg);
  border: 1px solid var(--accent-border);
  border-radius: var(--radius-sm);
  font-size: 12px;
  color: var(--accent);
}

.tag-remove { cursor: pointer; font-size: 14px; color: var(--text-3); line-height: 1; transition: color var(--transition); }
.tag-remove:hover { color: var(--error); }

.tag-input-wrap { position: relative; }

.tag-auto-input {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 13px;
  outline: none;
  background: var(--surface);
  color: var(--text);
  font-family: var(--font-body);
  transition: all var(--transition);
}

.tag-auto-input:focus { border-color: var(--accent); box-shadow: 0 0 0 2px var(--ai-glow); }
.tag-auto-input::placeholder { color: var(--text-4); }

.tag-dropdown {
  display: none;
  position: absolute;
  top: 100%;
  left: 0; right: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-top: none;
  border-radius: 0 0 var(--radius) var(--radius);
  max-height: 150px;
  overflow-y: auto;
  z-index: 1000;
  box-shadow: var(--shadow-md);
}

.tag-dropdown.open { display: block; }

.tag-dropdown-item {
  padding: 7px 10px;
  cursor: pointer;
  font-size: 12px;
  border-bottom: 1px solid var(--border);
  color: var(--text-2);
  transition: background var(--transition);
}

.tag-dropdown-item:hover { background: var(--surface-2); }
.tag-dropdown-item.active { background: var(--accent-bg); color: var(--accent); font-weight: 600; }
.tag-dropdown-item .tag-match { font-weight: 700; color: var(--accent); }
.tag-dropdown-item .tag-group-hint { float: right; font-size: 10px; color: var(--text-4); }

.tag-dropdown-empty {
  padding: 8px;
  font-size: 12px;
  color: var(--text-4);
  text-align: center;
}

/* ===================== RESPONSIVE ===================== */
@media (max-width: 640px) {
  header h1 { font-size: 22px; }
  header p { font-size: 12px; }

  .search-container,
  .filters,
  .results,
  .history-bar,
  .search-tips,
  .search-analytics,
  .tag-autocomplete,
  .search-suggestions,
  .tag-wiki-panel,
  .confidence-bar,
  .ai-action-bar,
  .sort-toolbar,
  .ai-quality-panel,
  .ai-suggestions-panel,
  .ai-refresh-panel { padding-left: 12px; padding-right: 12px; }

  .search-box input,
  .latex-input-area textarea { font-size: 16px; }

  .result-card { padding: 12px; }
  .result-card h3 { font-size: 14px; }
  .mode-btn { padding: 7px 14px; font-size: 12px; }

  .sort-pill-text { display: none; }
  .sort-pill { padding: 5px 8px; }

  .ai-sug-reason { display: none; }
  .ai-sug-item { padding: 6px 8px; }
}