/* =============================================================
   Important Design Patterns (Java) — Enterprise Dark Theme
   Inspired by Linear / Vercel / GitHub Dark / Radix UI
   ============================================================= */

:root {
  --bg:           #09090b;
  --surface:      #111113;
  --card:         #18181b;
  --border:       #27272a;
  --border-light: #3f3f46;
  --text:         #fafafa;
  --muted:        #a1a1aa;
  --dim:          #52525b;

  --accent:  #6366f1;
  --accent2: #818cf8;
  --accent3: #a5b4fc;

  --green: #22c55e;
  --amber: #f59e0b;
  --coral: #f97316;
  --pink:  #ec4899;
  --teal:  #14b8a6;

  --sidebar-width: 272px;
  --header-height: 50px;
  --topbar-height: 40px;
  --radius:    6px;
  --radius-sm: 4px;

  --font:      'Segoe UI', system-ui, -apple-system, sans-serif;
  --font-mono: 'Cascadia Code', 'Fira Code', 'Consolas', monospace;

  --shadow:    0 1px 3px rgba(0,0,0,.4);
  --shadow-md: 0 4px 12px rgba(0,0,0,.5);
}

/* ── Light Mode ─────────────────────────────────────────── */
.light {
  --bg:           #fafaf9;
  --surface:      #f4f4f5;
  --card:         #ffffff;
  --border:       #e4e4e7;
  --border-light: #d4d4d8;
  --text:         #09090b;
  --muted:        #52525b;
  --dim:          #a1a1aa;
  --shadow:       0 1px 3px rgba(0,0,0,.06);
  --shadow-md:    0 4px 12px rgba(0,0,0,.08);
}

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

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 14px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
  transition: background-color .2s ease, color .2s ease;
}

/* ── Accessibility ─────────────────────────────────────── */
.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

/* ── Topbar ─────────────────────────────────────────────── */
.site-topbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--topbar-height);
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  z-index: 100;
}

.topbar-inner {
  display: flex;
  align-items: center;
  padding: 0 16px;
  width: 100%;
  height: 100%;
  gap: 0;
}

.topbar-brand {
  display: flex;
  align-items: center;
  gap: 7px;
  text-decoration: none;
  flex-shrink: 0;
  margin-right: 16px;
}

.topbar-logo-mark {
  background: var(--accent);
  color: #fff;
  font-size: 10px;
  font-weight: 800;
  padding: 2px 5px;
  border-radius: 4px;
  letter-spacing: .02em;
}

.topbar-logo-text {
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
  letter-spacing: -.01em;
}

.topbar-breadcrumb {
  display: flex;
  align-items: center;
  gap: 4px;
  flex: 1;
  overflow: hidden;
}

.topbar-bc-link {
  font-size: 12px;
  color: var(--muted);
  text-decoration: none;
  transition: color .12s;
  white-space: nowrap;
}
.topbar-bc-link:hover { color: var(--text); }

.topbar-bc-sep { font-size: 12px; color: var(--dim); }

.topbar-bc-current {
  font-size: 12px;
  color: var(--accent3);
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.topbar-theme-toggle {
  background: none;
  border: 1px solid var(--border);
  color: var(--muted);
  cursor: pointer;
  font-size: 13px;
  padding: 3px 8px;
  border-radius: var(--radius);
  transition: all .12s;
  flex-shrink: 0;
  margin-right: 8px;
  line-height: 1;
  font-family: var(--font);
}
.topbar-theme-toggle:hover { color: var(--text); border-color: var(--border-light); }

.icon-light { display: none; }
.icon-dark  { display: inline; }
.light .icon-dark  { display: none; }
.light .icon-light { display: inline; }

.topbar-request {
  font-size: 11px;
  font-weight: 500;
  color: var(--accent3);
  text-decoration: none;
  border: 1px solid rgba(99,102,241,.35);
  padding: 3px 10px;
  border-radius: var(--radius);
  transition: all .12s;
  flex-shrink: 0;
  white-space: nowrap;
}
.topbar-request:hover {
  background: rgba(99,102,241,.12);
  border-color: var(--accent);
  color: var(--text);
}

/* ── Layout ─────────────────────────────────────────────── */
.app-layout {
  display: flex;
  height: calc(100vh - var(--topbar-height));
  margin-top: var(--topbar-height);
  overflow: hidden;
}

/* ── Sidebar ─────────────────────────────────────────────── */
.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  background: var(--surface);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.sidebar-header {
  padding: 14px 14px 10px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.sidebar-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -.01em;
}

.sidebar-badge {
  display: inline-block;
  background: rgba(99,102,241,.15);
  color: var(--accent3);
  font-size: 10px;
  font-weight: 600;
  padding: 1px 6px;
  border-radius: 10px;
  margin-left: 6px;
  vertical-align: middle;
  letter-spacing: .03em;
}

.sidebar-subtitle {
  font-size: 11px;
  color: var(--dim);
  margin-top: 2px;
}

.sidebar-search-wrap {
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.sidebar-search {
  display: flex;
  align-items: center;
  gap: 7px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 5px 9px;
}

.sidebar-search .s-icon { color: var(--dim); font-size: 11px; flex-shrink: 0; }

.sidebar-search input {
  flex: 1;
  background: none;
  border: none;
  outline: none;
  color: var(--text);
  font-size: 12px;
  font-family: var(--font);
}
.sidebar-search input::placeholder { color: var(--dim); }

.sidebar-nav {
  flex: 1;
  overflow-y: auto;
  padding: 6px 0 12px;
}

.sidebar-nav::-webkit-scrollbar { width: 3px; }
.sidebar-nav::-webkit-scrollbar-track { background: transparent; }
.sidebar-nav::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }

.nav-section { margin-bottom: 1px; }

.nav-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  cursor: pointer;
  border-left: 2px solid transparent;
  transition: all .12s ease;
  color: var(--muted);
  font-size: 13px;
  user-select: none;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin-right: 6px;
  text-decoration: none;
}
.nav-item:hover { color: var(--text); background: rgba(255,255,255,.04); }
.light .nav-item:hover { background: rgba(0,0,0,.04); }
.nav-item.active {
  color: var(--accent3);
  border-left-color: var(--accent);
  background: rgba(99,102,241,.08);
}

.nav-icon    { width: 16px; text-align: center; font-size: 13px; flex-shrink: 0; }
.nav-label   { flex: 1; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.nav-chevron { font-size: 9px; color: var(--dim); transition: transform .12s ease; flex-shrink: 0; }
.nav-section.open .nav-chevron { transform: rotate(90deg); }

.nav-subitems { display: none; }
.nav-section.open .nav-subitems { display: block; }

.nav-subitem {
  display: flex;
  align-items: center;
  padding: 4px 12px 4px 34px;
  cursor: pointer;
  color: var(--dim);
  font-size: 12px;
  transition: all .12s ease;
  border-left: 2px solid transparent;
  margin-right: 6px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  user-select: none;
  text-decoration: none;
}
.nav-subitem::before {
  content: '';
  width: 4px; height: 4px;
  border-radius: 50%;
  background: var(--border-light);
  margin-right: 8px;
  flex-shrink: 0;
  transition: background .12s;
}
.nav-subitem:hover { color: var(--muted); background: rgba(255,255,255,.02); }
.light .nav-subitem:hover { background: rgba(0,0,0,.02); }
.nav-subitem:hover::before { background: var(--accent); }
.nav-subitem.active { color: var(--accent2); border-left-color: var(--accent); }
.nav-subitem.active::before { background: var(--accent); }

.sidebar-footer {
  padding: 10px 14px;
  border-top: 1px solid var(--border);
  flex-shrink: 0;
}

.progress-meta {
  display: flex;
  justify-content: space-between;
  font-size: 11px;
  color: var(--dim);
  margin-bottom: 5px;
}

.progress-bar {
  height: 2px;
  background: var(--border);
  border-radius: 2px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  width: 0%;
  transition: width .4s ease;
}

/* ── Main Area ───────────────────────────────────────────── */
.main { flex: 1; display: flex; flex-direction: column; overflow: hidden; }

.main-header {
  height: var(--header-height);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  padding: 0 28px;
  flex-shrink: 0;
  background: var(--surface);
}

.breadcrumb { display: flex; align-items: center; gap: 6px; font-size: 13px; }
.bc-item { color: var(--dim); }
.bc-item.current { color: var(--text); font-weight: 500; }
.bc-sep { color: var(--border-light); font-size: 11px; }
.bc-active { color: var(--accent3); font-weight: 500; }

.main-content-wrap {
  flex: 1;
  overflow-y: auto;
  display: flex;
  justify-content: flex-start;
}
.main-content-wrap::-webkit-scrollbar { width: 5px; }
.main-content-wrap::-webkit-scrollbar-track { background: transparent; }
.main-content-wrap::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

.main-content {
  padding: 32px 48px 64px;
  max-width: 960px;
  width: 100%;
}

/* ── Typography ──────────────────────────────────────────── */
.page-title {
  font-size: 26px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -.025em;
  margin-bottom: 8px;
  line-height: 1.2;
}

.page-desc {
  font-size: 14px;
  color: var(--muted);
  margin-bottom: 28px;
  max-width: 680px;
  line-height: 1.65;
}

h2.sec {
  font-size: 18px;
  font-weight: 600;
  color: var(--text);
  letter-spacing: -.01em;
  margin: 36px 0 14px;
  padding-bottom: 9px;
  border-bottom: 1px solid var(--border);
}
h2.sec:first-of-type { margin-top: 0; }

h3.sub {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  margin: 22px 0 9px;
}

h4.lbl {
  font-size: 11px;
  font-weight: 700;
  color: var(--dim);
  text-transform: uppercase;
  letter-spacing: .07em;
  margin: 18px 0 7px;
}

p {
  color: var(--muted);
  margin-bottom: 12px;
  line-height: 1.72;
  font-size: 14px;
}
p:last-child { margin-bottom: 0; }

strong { color: var(--text); font-weight: 600; }
em { color: var(--accent3); font-style: italic; }

ul, ol { padding-left: 22px; color: var(--muted); margin: 8px 0 14px; line-height: 1.75; }
li { margin-bottom: 4px; font-size: 14px; }
li::marker { color: var(--border-light); }
ul.compact li { margin-bottom: 2px; font-size: 13px; }

hr { border: none; border-top: 1px solid var(--border); margin: 24px 0; }

/* ── Tabs ────────────────────────────────────────────────── */
.tabs { margin: 20px 0; }

.tab-nav {
  display: flex;
  border-bottom: 1px solid var(--border);
  margin-bottom: 20px;
  overflow-x: auto;
  gap: 0;
}
.tab-nav::-webkit-scrollbar { height: 0; }

.tab-btn {
  padding: 7px 16px;
  font-size: 13px;
  color: var(--muted);
  cursor: pointer;
  border: none;
  background: none;
  border-bottom: 2px solid transparent;
  transition: all .12s ease;
  white-space: nowrap;
  font-family: var(--font);
  margin-bottom: -1px;
  user-select: none;
}
.tab-btn:hover { color: var(--text); }
.tab-btn.active { color: var(--accent3); border-bottom-color: var(--accent); }

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ── Code Blocks ─────────────────────────────────────────── */
.code-block {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin: 14px 0;
}

.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 14px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.code-label { font-size: 12px; color: var(--dim); }
.code-lang {
  font-size: 10px;
  font-weight: 600;
  background: var(--border);
  color: var(--muted);
  padding: 2px 7px;
  border-radius: 3px;
  letter-spacing: .03em;
}

.code-block pre { padding: 16px; overflow-x: auto; margin: 0; }
.code-block code {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text);
  line-height: 1.65;
  white-space: pre;
}

p code, li code, td code {
  background: rgba(99,102,241,.1);
  border: 1px solid rgba(99,102,241,.15);
  border-radius: 3px;
  padding: 1px 5px;
  font-size: 12px;
  font-family: var(--font-mono);
  color: var(--accent3);
}

/* Syntax highlighting tokens */
.kw  { color: #818cf8; font-weight: 600; }
.str { color: #86efac; }
.cmt { color: #4a4a5a; font-style: italic; }
.cls { color: #f9a8d4; }
.fn  { color: #67e8f9; }
.num { color: #fda4af; }
.ann { color: #fbbf24; }
.op  { color: #a1a1aa; }
.typ { color: #c4b5fd; }

/* ── Callouts ─────────────────────────────────────────────── */
.callout {
  border-radius: var(--radius);
  padding: 12px 14px;
  margin: 14px 0;
  border-left: 3px solid;
  display: flex;
  gap: 10px;
}
.callout-icon { font-size: 14px; flex-shrink: 0; margin-top: 1px; line-height: 1.7; }
.callout-inner { flex: 1; }
.callout-title { font-size: 12px; font-weight: 700; margin-bottom: 4px; text-transform: uppercase; letter-spacing: .05em; }
.callout-body { font-size: 13px; color: var(--muted); line-height: 1.6; margin: 0; }
.callout-body code { background: rgba(255,255,255,.05); padding: 1px 5px; border-radius: 3px; font-size: 12px; color: var(--text); font-family: var(--font-mono); border: 1px solid var(--border); }

.callout.info    { background: rgba(99,102,241,.07); border-color: var(--accent); }
.callout.info    .callout-title { color: var(--accent3); }
.callout.warn    { background: rgba(245,158,11,.07); border-color: var(--amber); }
.callout.warn    .callout-title { color: var(--amber); }
.callout.danger  { background: rgba(249,115,22,.07); border-color: var(--coral); }
.callout.danger  .callout-title { color: var(--coral); }
.callout.success { background: rgba(34,197,94,.07);  border-color: var(--green); }
.callout.success .callout-title { color: var(--green); }
.callout.tip     { background: rgba(20,184,166,.07); border-color: var(--teal); }
.callout.tip     .callout-title { color: var(--teal); }

/* ── Mental Model / Insight ──────────────────────────────── */
.mental-model {
  background: rgba(99,102,241,.06);
  border: 1px solid rgba(99,102,241,.2);
  border-radius: var(--radius);
  padding: 14px 16px;
  margin: 14px 0;
}
.mental-model-label {
  font-size: 10px;
  font-weight: 700;
  color: var(--accent2);
  text-transform: uppercase;
  letter-spacing: .08em;
  margin-bottom: 8px;
}
.mental-model p { font-size: 13px; color: var(--muted); margin: 0; line-height: 1.65; }

.insight {
  background: rgba(20,184,166,.06);
  border: 1px solid rgba(20,184,166,.25);
  border-radius: var(--radius);
  padding: 13px 15px;
  margin: 16px 0;
  display: flex;
  gap: 10px;
  align-items: flex-start;
}
.insight-icon { color: var(--teal); font-size: 15px; flex-shrink: 0; }
.insight-text { font-size: 13px; color: var(--muted); font-style: italic; margin: 0; line-height: 1.6; }
.insight-text strong { color: var(--teal); }

/* ── Tables ───────────────────────────────────────────────── */
.table-wrap {
  overflow-x: auto;
  margin: 14px 0;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}
table { width: 100%; border-collapse: collapse; font-size: 13px; }
thead th {
  background: var(--surface);
  color: var(--muted);
  font-weight: 600;
  text-align: left;
  padding: 9px 13px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .05em;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}
td {
  padding: 9px 13px;
  color: var(--muted);
  border-bottom: 1px solid var(--border);
  vertical-align: top;
  line-height: 1.55;
}
tr:last-child td { border-bottom: none; }
tr:hover td { background: rgba(255,255,255,.02); }
.light tr:hover td { background: rgba(0,0,0,.02); }
td strong { color: var(--text); }
tr.highlight td { background: rgba(99,102,241,.05); }
tr.good td { background: rgba(34,197,94,.04); }
tr.bad  td { background: rgba(249,115,22,.04); }

/* ── Cards ────────────────────────────────────────────────── */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  margin: 12px 0;
}
.card-title { font-size: 13px; font-weight: 600; color: var(--text); margin-bottom: 8px; }

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 12px;
  margin: 14px 0;
}

/* ── Badges ───────────────────────────────────────────────── */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  border-radius: 12px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .02em;
  white-space: nowrap;
}
.b-accent  { background: rgba(99,102,241,.15);  color: var(--accent3); }
.b-green   { background: rgba(34,197,94,.12);   color: var(--green); }
.b-amber   { background: rgba(245,158,11,.12);  color: var(--amber); }
.b-coral   { background: rgba(249,115,22,.12);  color: var(--coral); }
.b-teal    { background: rgba(20,184,166,.12);  color: var(--teal); }
.b-dim     { background: var(--surface); color: var(--dim); border: 1px solid var(--border); }

/* ── Collapsibles ─────────────────────────────────────────── */
.collapse {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 10px 0;
  overflow: hidden;
}
.collapse-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 11px 15px;
  cursor: pointer;
  background: var(--surface);
  transition: background .12s ease;
  user-select: none;
}
.collapse-header:hover { background: var(--card); }
.collapse-title { font-size: 13px; font-weight: 600; color: var(--text); }
.collapse-icon  { color: var(--dim); font-size: 10px; transition: transform .12s ease; }
.collapse.open .collapse-icon { transform: rotate(90deg); }

.collapse-body {
  display: none;
  padding: 16px;
  border-top: 1px solid var(--border);
  background: var(--card);
}
.collapse.open .collapse-body { display: block; }

/* ── Diagram / ASCII ──────────────────────────────────────── */
.diagram {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  margin: 14px 0;
  overflow-x: auto;
}
.diagram-label {
  font-size: 10px;
  color: var(--dim);
  text-transform: uppercase;
  letter-spacing: .07em;
  margin-bottom: 12px;
  font-weight: 600;
}
.diagram pre {
  background: none; border: none; padding: 0; margin: 0;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.55;
  white-space: pre;
}

/* ── Steps ────────────────────────────────────────────────── */
.steps { margin: 16px 0; }
.step {
  display: flex;
  gap: 14px;
  margin-bottom: 16px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}
.step:last-child { border-bottom: none; margin-bottom: 0; padding-bottom: 0; }
.step-num {
  flex-shrink: 0;
  width: 24px; height: 24px;
  border-radius: 50%;
  background: rgba(99,102,241,.15);
  color: var(--accent3);
  font-size: 11px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  margin-top: 1px;
}
.step-content h4 { font-size: 13px; font-weight: 600; color: var(--text); margin-bottom: 5px; }
.step-content p  { font-size: 13px; color: var(--muted); margin: 0; line-height: 1.6; }

/* ── Compare Grid ─────────────────────────────────────────── */
.compare-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin: 14px 0; }
.cmp-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px;
}
.cmp-card.good    { border-top: 2px solid var(--green); }
.cmp-card.bad     { border-top: 2px solid var(--coral); }
.cmp-card.neutral { border-top: 2px solid var(--accent); }

.cmp-label { font-size: 11px; font-weight: 700; text-transform: uppercase; letter-spacing: .05em; margin-bottom: 10px; }
.cmp-card.good    .cmp-label { color: var(--green); }
.cmp-card.bad     .cmp-label { color: var(--coral); }
.cmp-card.neutral .cmp-label { color: var(--accent3); }
.cmp-card ul { margin: 0; padding-left: 16px; }
.cmp-card li { font-size: 13px; color: var(--muted); margin-bottom: 5px; }

/* ── Interview Questions ──────────────────────────────────── */
.interview-section {
  margin: 36px 0 0;
  border-top: 1px solid var(--border);
  padding-top: 24px;
}

.interview-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}
.interview-header h2 {
  font-size: 16px; font-weight: 700; color: var(--text);
  letter-spacing: -.01em; margin: 0;
}
.interview-badge {
  font-size: 10px; font-weight: 700;
  color: var(--amber);
  background: rgba(245,158,11,.12);
  border: 1px solid rgba(245,158,11,.2);
  padding: 2px 8px;
  border-radius: 10px;
  text-transform: uppercase;
  letter-spacing: .06em;
  white-space: nowrap;
}

.interview-q {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 8px 0;
  overflow: hidden;
}
.interview-q .collapse-header { background: var(--surface); }
.interview-q .collapse-header:hover { background: rgba(245,158,11,.05); }
.interview-q.open .collapse-header {
  border-bottom: 1px solid var(--border);
  background: rgba(245,158,11,.04);
}
.interview-q .collapse-title { color: var(--muted); font-size: 13px; font-weight: 500; }
.interview-q.open .collapse-title { color: var(--text); }

.interview-answer {
  padding: 16px;
  background: var(--card);
  font-size: 13px;
  color: var(--muted);
  line-height: 1.72;
}
.interview-answer p { margin-bottom: 10px; font-size: 13px; }
.interview-answer p:last-child { margin-bottom: 0; }
.interview-answer ul, .interview-answer ol { margin: 6px 0 10px; padding-left: 20px; }
.interview-answer li { font-size: 13px; margin-bottom: 4px; }
.interview-answer strong { color: var(--text); }
.interview-answer code { background: rgba(99,102,241,.1); border: 1px solid rgba(99,102,241,.15); border-radius: 3px; padding: 1px 5px; font-size: 11.5px; font-family: var(--font-mono); color: var(--accent3); }

/* ── Variant label pills ──────────────────────────────────── */
.var-label {
  display: inline-block;
  font-size: 10px; font-weight: 700;
  padding: 1px 8px; border-radius: 3px;
  letter-spacing: .05em;
  text-transform: uppercase;
  margin-bottom: 6px;
  margin-top: 4px;
}
.var-good      { background: rgba(34,197,94,.15);  color: var(--green); }
.var-avoid     { background: rgba(249,115,22,.15); color: var(--coral); }
.var-alt       { background: rgba(99,102,241,.15); color: var(--accent3); }
.var-preferred { background: rgba(20,184,166,.15); color: var(--teal); }
.var-warn      { background: rgba(245,158,11,.15); color: var(--amber); }

/* ── Subtopic nav (in-content strip) ─────────────────────── */
.subtopic-nav {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 16px;
  margin-top: 40px;
  background: var(--surface);
}
.subtopic-nav-label {
  font-size: 10px; font-weight: 700;
  color: var(--dim);
  text-transform: uppercase;
  letter-spacing: .07em;
  margin-bottom: 8px;
}
.subtopic-nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.subtopic-nav-link {
  font-size: 12px;
  color: var(--muted);
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 3px 10px;
  text-decoration: none;
  transition: all .12s;
}
.subtopic-nav-link:hover { color: var(--text); border-color: var(--border-light); }
.subtopic-nav-link.active {
  color: var(--accent3);
  border-color: var(--accent);
  background: rgba(99,102,241,.08);
}

/* ── Prev / Next footer ───────────────────────────────────── */
.page-nav-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  gap: 12px;
}
.page-nav-btn {
  font-size: 13px;
  color: var(--muted);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: color .12s;
}
.page-nav-btn:hover { color: var(--accent3); }
.page-nav-btn.next { margin-left: auto; }

/* ── Misc utilities ───────────────────────────────────────── */
.flex { display: flex; }
.flex-wrap { flex-wrap: wrap; }
.gap-6 { gap: 6px; }
.gap-8 { gap: 8px; }
.items-center { align-items: center; }
.mt-4  { margin-top: 4px; }
.mt-8  { margin-top: 8px; }
.mt-12 { margin-top: 12px; }
.mt-16 { margin-top: 16px; }
.mb-0  { margin-bottom: 0 !important; }
.mb-8  { margin-bottom: 8px; }
.text-muted  { color: var(--muted); }
.text-dim    { color: var(--dim); }
.text-accent { color: var(--accent3); }
.text-green  { color: var(--green); }
.text-amber  { color: var(--amber); }
.text-coral  { color: var(--coral); }
.text-teal   { color: var(--teal); }
.text-sm { font-size: 12px; }
.text-xs { font-size: 11px; }
.block { display: block; }

[id] { scroll-margin-top: 16px; }

/* ── Light mode: keep code blocks dark ───────────────────── */
.light .code-block              { background: #18181b; border-color: #27272a; }
.light .code-block .code-header { background: #111113; border-color: #27272a; }
.light .code-block .code-label  { color: #71717a; }
.light .code-block .code-lang   { background: #27272a; color: #a1a1aa; }
.light .code-block code         { color: #fafafa; }
.light .diagram                 { background: #18181b; border-color: #27272a; }
.light .diagram .diagram-label  { color: #71717a; }
.light .diagram pre             { color: #a1a1aa; }
.light .callout-body code       { background: rgba(0,0,0,.06); color: #09090b; border-color: #d4d4d8; }

/* ── Mobile responsive ────────────────────────────────────── */
@media (max-width: 768px) {
  :root { --sidebar-width: 0px; }

  .sidebar {
    position: fixed;
    left: -280px;
    top: var(--topbar-height);
    height: calc(100vh - var(--topbar-height));
    width: 280px;
    z-index: 50;
    transition: left .2s ease;
    box-shadow: var(--shadow-md);
  }

  .sidebar.open { left: 0; }

  .main-content { padding: 20px 20px 48px; }

  .compare-grid { grid-template-columns: 1fr; }

  .topbar-breadcrumb { display: none; }
}