/* ============================================================
   Components - Dropdown navigation, breadcrumbs, and
   additional UI elements for the shared nav system.
   ============================================================ */

/* --- Nav Dropdown --- */
.nav-dropdown {
  position: relative;
}

.nav-dropdown > .nav-link {
  cursor: pointer;
}

.dropdown-arrow {
  font-size: 0.7em;
  margin-left: 0.15em;
  display: inline-block;
  transition: transform 0.2s ease;
}

.nav-dropdown-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 280px;
  max-height: 70vh;
  overflow-y: auto;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: 0 8px 24px var(--shadow);
  padding: 0.5rem 0;
  z-index: 1100;
}

.nav-dropdown-menu a {
  display: block;
  padding: 0.4rem 1rem;
  font-size: 0.88rem;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: var(--text-secondary);
  text-decoration: none;
  transition: background-color 0.15s ease, color 0.15s ease;
  white-space: nowrap;
}

.nav-dropdown-menu a:hover {
  background: var(--bg-secondary);
  color: var(--accent);
  text-decoration: none;
}

.nav-dropdown-menu a.active {
  color: var(--accent);
  font-weight: 600;
  background: var(--bg-secondary);
}

.nav-dropdown-group {
  padding: 0.5rem 1rem 0.2rem;
  font-size: 0.75rem;
  font-weight: 700;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-top: 1px solid var(--border-light);
  margin-top: 0.25rem;
}

.nav-dropdown-group:first-child {
  border-top: none;
  margin-top: 0;
}

/* Desktop: hover to open */
@media (min-width: 769px) {
  .nav-dropdown:hover > .nav-dropdown-menu {
    display: block;
  }

  .nav-dropdown:hover > .nav-link .dropdown-arrow {
    transform: rotate(180deg);
  }
}

/* Mobile: tap to open via .active class */
@media (max-width: 768px) {
  .nav-dropdown-menu {
    position: static;
    box-shadow: none;
    border: none;
    border-left: 2px solid var(--border-light);
    border-radius: 0;
    margin-left: 1rem;
    padding: 0;
    min-width: auto;
    max-height: none;
    background: transparent;
  }

  .nav-dropdown.active > .nav-dropdown-menu {
    display: block;
  }

  .nav-dropdown.active > .nav-link .dropdown-arrow {
    transform: rotate(180deg);
  }

  .nav-dropdown-menu a {
    padding: 0.35rem 0.75rem;
    font-size: 0.85rem;
  }

  .nav-dropdown-group {
    padding: 0.4rem 0.75rem 0.15rem;
    font-size: 0.72rem;
  }
}

/* --- Breadcrumbs --- */
.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.25rem;
  padding: 0.5rem 0;
  font-size: 0.85rem;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: var(--text-muted);
}

.breadcrumb-link {
  color: var(--link);
  text-decoration: none;
}

.breadcrumb-link:hover {
  color: var(--link-hover);
  text-decoration: underline;
}

.breadcrumb-current {
  color: var(--text-primary);
  font-weight: 600;
}

.breadcrumb-divider {
  color: var(--text-muted);
  margin: 0 0.1rem;
}

.breadcrumb-separator {
  color: var(--text-secondary);
}

/* --- Search Icon in Nav --- */
.nav-link[aria-label="Search"] {
  font-size: 1.1rem;
  line-height: 1;
}

/* ============================================================
   Chapter Header Card
   ============================================================ */
.chapter-header { padding: 2rem 0; border-bottom: 2px solid var(--border); margin-bottom: 2rem; }
.chapter-header .chapter-number { font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.85rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.1em; }
.chapter-header h1 { font-size: 2.2rem; margin: 0.5rem 0; }
.chapter-header .chapter-meta { display: flex; gap: 0.75rem; flex-wrap: wrap; margin-top: 0.75rem; }

/* ============================================================
   Badges (Part, Depth, Phase)
   ============================================================ */
.badge { display: inline-flex; align-items: center; padding: 0.2rem 0.65rem; border-radius: 4px; font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.78rem; font-weight: 600; letter-spacing: 0.02em; }
.badge-part-i { background: color-mix(in srgb, var(--part-i) 15%, transparent); color: var(--part-i); border: 1px solid color-mix(in srgb, var(--part-i) 30%, transparent); }
.badge-part-ii { background: color-mix(in srgb, var(--part-ii) 15%, transparent); color: var(--part-ii); border: 1px solid color-mix(in srgb, var(--part-ii) 30%, transparent); }
.badge-part-iii { background: color-mix(in srgb, var(--part-iii) 15%, transparent); color: var(--part-iii); border: 1px solid color-mix(in srgb, var(--part-iii) 30%, transparent); }
.badge-part-iv { background: color-mix(in srgb, var(--part-iv) 15%, transparent); color: var(--part-iv); border: 1px solid color-mix(in srgb, var(--part-iv) 30%, transparent); }
.badge-deep { background: color-mix(in srgb, var(--depth-deep) 15%, transparent); color: var(--depth-deep); border: 1px solid color-mix(in srgb, var(--depth-deep) 30%, transparent); }
.badge-moderate { background: color-mix(in srgb, var(--depth-moderate) 15%, transparent); color: var(--depth-moderate); border: 1px solid color-mix(in srgb, var(--depth-moderate) 30%, transparent); }
.badge-survey { background: color-mix(in srgb, var(--depth-survey) 15%, transparent); color: var(--depth-survey); border: 1px solid color-mix(in srgb, var(--depth-survey) 30%, transparent); }

/* ============================================================
   Section Outline Sidebar (sticky "On this page")
   ============================================================ */
.page-sidebar { position: sticky; top: 5rem; max-height: calc(100vh - 6rem); overflow-y: auto; padding-right: 1rem; }
.page-sidebar h3 { font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.8rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.1em; color: var(--text-muted); margin-bottom: 0.75rem; }
.page-sidebar ul { list-style: none; padding: 0; margin: 0; }
.page-sidebar li { margin-bottom: 0.25rem; }
.page-sidebar a { display: block; padding: 0.25rem 0.5rem; border-left: 2px solid transparent; color: var(--text-secondary); text-decoration: none; font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.85rem; transition: border-color 0.2s, color 0.2s; }
.page-sidebar a:hover { color: var(--accent); }
.page-sidebar a.active { border-left-color: var(--accent); color: var(--accent); font-weight: 500; }
.page-sidebar .indent { padding-left: 1.25rem; }

/* ============================================================
   Equation Block
   ============================================================ */
.equation-block { background: var(--bg-secondary); border: 1px solid var(--border-light); border-radius: 8px; padding: 1.25rem 1.5rem; margin: 1.5rem 0; text-align: center; position: relative; overflow-x: auto; }
.equation-block .equation-number { position: absolute; right: 1rem; top: 50%; transform: translateY(-50%); color: var(--text-muted); font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.85rem; }
.equation-block .equation-context { font-size: 0.85rem; color: var(--text-secondary); margin-top: 0.5rem; font-style: italic; }

/* ============================================================
   Figure Placeholder Card
   ============================================================ */
.figure-card { background: var(--bg-card); border: 1px solid var(--border-light); border-radius: 8px; padding: 1.25rem; margin: 1rem 0; }
.figure-card .figure-type { font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.75rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em; color: var(--text-muted); margin-bottom: 0.25rem; }
.figure-card .figure-title { font-weight: 600; margin-bottom: 0.5rem; }
.figure-card .figure-desc { font-size: 0.95rem; color: var(--text-secondary); }

/* ============================================================
   Prerequisite Chain
   ============================================================ */
.prereq-chain { display: flex; align-items: center; gap: 0.5rem; flex-wrap: wrap; margin: 1rem 0; font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.9rem; }
.prereq-chain .prereq-item { padding: 0.35rem 0.75rem; border-radius: 6px; background: var(--bg-secondary); border: 1px solid var(--border-light); color: var(--text-secondary); text-decoration: none; transition: background 0.2s; }
.prereq-chain .prereq-item:hover { background: var(--bg-card); color: var(--accent); }
.prereq-chain .prereq-arrow { color: var(--text-muted); }
.prereq-chain .prereq-current { background: var(--accent); color: white; border-color: var(--accent); }

/* ============================================================
   Progress Bar
   ============================================================ */
.progress-bar { height: 8px; background: var(--bg-secondary); border-radius: 4px; overflow: hidden; margin: 0.5rem 0; }
.progress-bar-fill { height: 100%; border-radius: 4px; transition: width 0.5s ease; }
.progress-bar-fill.complete { background: var(--progress-complete); }
.progress-bar-fill.active { background: var(--progress-active); }
.progress-bar-fill.pending { background: var(--progress-pending); }
.progress-label { font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.85rem; color: var(--text-secondary); display: flex; justify-content: space-between; }

/* ============================================================
   Search Input
   ============================================================ */
.search-input { display: flex; align-items: center; background: var(--bg-secondary); border: 1px solid var(--border); border-radius: 6px; padding: 0.4rem 0.75rem; transition: border-color 0.2s, box-shadow 0.2s; }
.search-input:focus-within { border-color: var(--accent); box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 20%, transparent); }
.search-input input { border: none; background: transparent; color: var(--text-primary); font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.9rem; outline: none; width: 100%; }
.search-input .search-icon { color: var(--text-muted); margin-right: 0.5rem; flex-shrink: 0; }

/* ============================================================
   Tag / Filter Pills
   ============================================================ */
.tag-pills { display: flex; flex-wrap: wrap; gap: 0.5rem; margin: 1rem 0; }
.tag-pill { padding: 0.3rem 0.75rem; border-radius: 20px; font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.8rem; border: 1px solid var(--border); color: var(--text-secondary); background: transparent; cursor: pointer; transition: all 0.2s; }
.tag-pill:hover { border-color: var(--accent); color: var(--accent); }
.tag-pill.active { background: var(--accent); color: white; border-color: var(--accent); }

/* ============================================================
   Reading Path Card
   ============================================================ */
.path-card { background: var(--bg-card); border: 1px solid var(--border-light); border-radius: 8px; padding: 1.25rem; margin: 1rem 0; box-shadow: 0 2px 8px var(--shadow); }
.path-card h3 { margin: 0 0 0.5rem; font-size: 1.1rem; }
.path-card .path-chapters { display: flex; align-items: center; gap: 0.3rem; flex-wrap: wrap; margin: 0.75rem 0; font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.85rem; }
.path-card .path-chapter { padding: 0.2rem 0.5rem; border-radius: 4px; background: var(--bg-secondary); }
.path-card .path-stats { font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.85rem; color: var(--text-muted); }

/* ============================================================
   Status Cards (dashboard)
   ============================================================ */
.status-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 1rem; }
.status-card { background: var(--bg-card); border: 1px solid var(--border-light); border-radius: 8px; padding: 1rem; text-align: center; transition: box-shadow 0.2s; }
.status-card:hover { box-shadow: 0 4px 16px var(--shadow-hover); }
.status-card .status-indicator { display: inline-block; width: 8px; height: 8px; border-radius: 50%; margin-right: 0.5rem; }
.status-card .status-indicator.not-started { background: var(--progress-pending); }
.status-card .status-indicator.drafting { background: var(--progress-active); }
.status-card .status-indicator.review { background: #ff9800; }
.status-card .status-indicator.complete { background: var(--progress-complete); }

/* ============================================================
   Chapter Nav (prev/next)
   ============================================================ */
.chapter-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin: 3rem 0 2rem; padding-top: 2rem; border-top: 1px solid var(--border); }
.chapter-nav a { display: block; padding: 1rem; border: 1px solid var(--border-light); border-radius: 8px; text-decoration: none; color: var(--text-primary); transition: border-color 0.2s, box-shadow 0.2s; }
.chapter-nav a:hover { border-color: var(--accent); box-shadow: 0 2px 8px var(--shadow); }
.chapter-nav .nav-label { font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif); font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--text-muted); }
.chapter-nav .nav-title { font-weight: 600; margin-top: 0.25rem; }
.chapter-nav .next { text-align: right; }

/* ============================================================
   Two-column Chapter Layout
   ============================================================ */
.chapter-layout { display: grid; grid-template-columns: 1fr 240px; gap: 2rem; }
@media (max-width: 1024px) { .chapter-layout { grid-template-columns: 1fr; } .page-sidebar { display: none; } }

/* ============================================================
   Section Containers
   ============================================================ */
.chapter-section { margin-bottom: 2.5rem; scroll-margin-top: 5rem; }
.chapter-section h2 { font-size: 1.5rem; padding-bottom: 0.5rem; border-bottom: 1px solid var(--border-light); margin-bottom: 1rem; }
.chapter-section h3 { font-size: 1.2rem; margin-bottom: 0.75rem; }

/* ============================================================
   KaTeX Theme Overrides
   ============================================================ */
.katex { color: var(--text-primary); }
[data-theme="dark"] .katex .katex-html { color: var(--text-primary); }

/* ============================================================
   Context Pack Cards
   ============================================================ */
.context-card {
  border: 1px solid var(--border-light);
  border-radius: 8px;
  padding: 1.25rem;
  margin: 1rem 0;
  background: var(--bg-card);
}
.context-card h4 {
  margin-top: 0;
  color: var(--accent);
}
.teaching-insight {
  margin: 0.5rem 0;
  padding: 0.5rem 0.75rem;
  border-left: 3px solid var(--accent);
  background: var(--bg-secondary);
  border-radius: 0 4px 4px 0;
}
.logic-flow {
  margin: 0.5rem 0;
  padding: 0.5rem 0.75rem;
  color: var(--text-secondary);
}
.misconception {
  margin: 0.5rem 0;
  padding: 0.5rem 0.75rem;
  border-left: 3px solid #e65100;
  background: color-mix(in srgb, #e65100 8%, transparent);
  border-radius: 0 4px 4px 0;
}
.example {
  margin: 0.5rem 0;
  padding: 0.5rem 0.75rem;
  border-left: 3px solid #1565c0;
  background: color-mix(in srgb, #1565c0 8%, transparent);
  border-radius: 0 4px 4px 0;
}
.code-connection {
  margin: 0.5rem 0;
  padding: 0.5rem 0.75rem;
  font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif);
  font-size: 0.9rem;
  color: var(--text-muted);
}
.code-connection code {
  background: var(--bg-code);
  padding: 0.1em 0.3em;
  border-radius: 3px;
  font-size: 0.85em;
}

/* ============================================================
   Page Navigation (prev/next for prompt/context pages)
   ============================================================ */
.page-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin: 2rem 0;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-light);
  gap: 1rem;
}
.page-nav a {
  font-weight: 600;
  text-decoration: none;
  color: var(--accent);
}
.page-nav a:hover {
  color: var(--accent-hover);
}

/* ============================================================
   QA Score Ring
   ============================================================ */
.score-ring {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: conic-gradient(var(--progress-complete) 0% 93.3%, var(--border-light) 93.3%);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 1rem auto;
}
.score-ring-inner {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background: var(--bg-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: 700;
  font-family: var(--font-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif);
  color: var(--text-primary);
}

/* ============================================================
   Validator Cards
   ============================================================ */
.validator-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: 8px;
  padding: 1.25rem;
  margin: 1rem 0;
}
.validator-card h3 {
  margin-top: 0;
}
.pass-badge {
  display: inline-flex;
  align-items: center;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-family: var(--font-ui, -apple-system, sans-serif);
  font-size: 0.75rem;
  font-weight: 600;
}
.pass-badge.pass {
  background: color-mix(in srgb, var(--progress-complete) 15%, transparent);
  color: var(--progress-complete);
}
.pass-badge.fail {
  background: color-mix(in srgb, var(--depth-deep) 15%, transparent);
  color: var(--depth-deep);
}

/* ============================================================
   CSS-only Tabs
   ============================================================ */
.tabs input[type="radio"] { display: none; }
.tabs .tab-labels { display: flex; gap: 0; border-bottom: 2px solid var(--border); margin-bottom: 1.5rem; }
.tabs .tab-label { padding: 0.75rem 1.25rem; cursor: pointer; font-family: var(--font-ui, -apple-system, sans-serif); font-size: 0.9rem; font-weight: 500; color: var(--text-secondary); border-bottom: 2px solid transparent; margin-bottom: -2px; transition: color 0.2s, border-color 0.2s; }
.tabs .tab-label:hover { color: var(--accent); }
.tabs .tab-content { display: none; }
.tabs input#tab1:checked ~ .tab-labels .tab-label[for="tab1"],
.tabs input#tab2:checked ~ .tab-labels .tab-label[for="tab2"],
.tabs input#tab3:checked ~ .tab-labels .tab-label[for="tab3"] { color: var(--accent); border-bottom-color: var(--accent); }
.tabs input#tab1:checked ~ .tab-content.tab1,
.tabs input#tab2:checked ~ .tab-content.tab2,
.tabs input#tab3:checked ~ .tab-content.tab3 { display: block; }

/* ============================================================
   Responsive Overrides
   ============================================================ */
@media (max-width: 768px) {
  .chapter-nav { grid-template-columns: 1fr; }
  .chapter-header h1 { font-size: 1.6rem; }
  .status-grid { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); }
  .prereq-chain { font-size: 0.8rem; }
  .equation-block { padding: 1rem; }
}
@media (max-width: 480px) {
  .chapter-header h1 { font-size: 1.3rem; }
  .badge { font-size: 0.72rem; padding: 0.15rem 0.5rem; }
  .chapter-nav a { padding: 0.75rem; min-height: 44px; }
  .tag-pill { min-height: 44px; display: inline-flex; align-items: center; }
  .prereq-chain .prereq-item { min-height: 44px; display: inline-flex; align-items: center; }
}