/* ==========================================================================
   AMZPrep — Masterclass Theme System (Dark / Light)
   ========================================================================== */

:root[data-theme="dark"] {
  --bg: #0a0e17;
  --bg2: #0f1422;
  --panel: #151c2e;
  --panel2: #1b243b;
  --panel3: #222d4a;
  --border: #243049;
  --border2: #2e3e5e;
  --text: #f0f4fc;
  --muted: #94a3b8;
  --faint: #64748b;
  
  --accent: #ff9900;
  --accent-hover: #ffad33;
  --accent-dim: rgba(255, 153, 0, 0.12);
  --accent-border: rgba(255, 153, 0, 0.35);
  
  --link: #60a5fa;
  --green: #34d399;
  --green-dim: rgba(52, 211, 153, 0.12);
  --yellow: #fbbf24;
  --yellow-dim: rgba(251, 191, 36, 0.12);
  --red: #f43f5e;
  --red-dim: rgba(244, 63, 94, 0.12);
  --blue: #38bdf8;
  --blue-dim: rgba(56, 189, 248, 0.12);
  --purple: #c084fc;
  
  --code-bg: #0c111c;
  --code-header: #131a2b;
  --code-border: #212c44;
  --code-text: #e2e8f0;
  
  --tok-kw: #f472b6;
  --tok-type: #38bdf8;
  --tok-str: #4ade80;
  --tok-comm: #64748b;
  --tok-ann: #fbbf24;
  --tok-num: #fb923c;
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.35);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.45);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.55);
}

:root[data-theme="light"] {
  --bg: #f8fafc;
  --bg2: #f1f5f9;
  --panel: #ffffff;
  --panel2: #f8fafc;
  --panel3: #f1f5f9;
  --border: #e2e8f0;
  --border2: #cbd5e1;
  --text: #0f172a;
  --muted: #475569;
  --faint: #94a3b8;
  
  --accent: #e07c00;
  --accent-hover: #c66e00;
  --accent-dim: rgba(224, 124, 0, 0.10);
  --accent-border: rgba(224, 124, 0, 0.30);
  
  --link: #2563eb;
  --green: #059669;
  --green-dim: rgba(5, 150, 105, 0.08);
  --yellow: #d97706;
  --yellow-dim: rgba(217, 119, 6, 0.08);
  --red: #e11d48;
  --red-dim: rgba(225, 29, 72, 0.08);
  --blue: #0284c7;
  --blue-dim: rgba(2, 132, 199, 0.08);
  --purple: #9333ea;
  
  --code-bg: #f8fafc;
  --code-header: #f1f5f9;
  --code-border: #e2e8f0;
  --code-text: #1e293b;
  
  --tok-kw: #be185d;
  --tok-type: #0369a1;
  --tok-str: #15803d;
  --tok-comm: #94a3b8;
  --tok-ann: #b45309;
  --tok-num: #c2410c;
  
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 16px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 10px 30px rgba(15, 23, 42, 0.12);
}

/* ==========================================================================
   Base Layout
   ========================================================================== */

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font: 15.5px/1.65 ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

#app {
  display: flex;
  min-height: 100vh;
}

/* ==========================================================================
   Sidebar Navigation
   ========================================================================== */

#sidebar {
  width: 290px;
  min-width: 290px;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  background: var(--bg2);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  padding: 16px 14px 12px;
  z-index: 30;
}

.side-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.logo {
  font-weight: 800;
  font-size: 21px;
  letter-spacing: -0.02em;
  color: var(--text);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 4px;
}

.logo span {
  color: var(--accent);
  background: linear-gradient(135deg, var(--accent), #ffbe53);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.side-head-actions {
  display: flex;
  align-items: center;
  gap: 6px;
}

#theme-btn {
  background: var(--panel);
  color: var(--muted);
  border: 1px solid var(--border);
  border-radius: 8px;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 15px;
  transition: all 0.15s ease;
}

#theme-btn:hover {
  color: var(--accent);
  border-color: var(--accent-border);
  background: var(--panel2);
}

.progress-wrap {
  margin: 0 0 12px;
}

.progress-text {
  font-size: 12px;
  font-weight: 500;
  color: var(--muted);
  margin-bottom: 6px;
  display: flex;
  justify-content: space-between;
}

.progress-bar {
  height: 6px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 99px;
  overflow: hidden;
}

#progress-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent), #ffca7b);
  border-radius: 99px;
  transition: width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.search-wrap {
  position: relative;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
}

.search-icon {
  position: absolute;
  left: 10px;
  color: var(--faint);
  pointer-events: none;
}

#search {
  width: 100%;
  background: var(--panel);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 8px 10px 8px 32px;
  border-radius: 9px;
  font-size: 13px;
  outline: none;
  transition: border-color 0.15s, box-shadow 0.15s;
}

#search:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

#toc {
  flex: 1;
  overflow-y: auto;
  padding-right: 4px;
}

.toc-group-title {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.1px;
  color: var(--faint);
  margin: 18px 6px 6px;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 8px;
  border-radius: 8px;
  padding: 2px 6px 2px 4px;
  margin-bottom: 2px;
  transition: background 0.12s;
}

.nav-item:hover {
  background: var(--panel);
}

.nav-item a {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 4px;
  color: var(--muted);
  text-decoration: none;
  font-size: 13.5px;
  line-height: 1.35;
  border-radius: 6px;
}

.nav-item a:hover {
  color: var(--text);
}

.nav-item.active {
  background: var(--panel);
  outline: 1px solid var(--accent-border);
}

.nav-item.active a {
  color: var(--text);
  font-weight: 600;
}

.nav-item a::before {
  content: "";
  width: 7px;
  height: 7px;
  border-radius: 50%;
  flex-shrink: 0;
  background: var(--dot, var(--faint));
}

.diff-Easy { --dot: var(--green); }
.diff-Medium { --dot: var(--yellow); }
.diff-Hard { --dot: var(--red); }
.diff-Guide { --dot: var(--blue); }

.donebox {
  accent-color: var(--accent);
  cursor: pointer;
  width: 14px;
  height: 14px;
  flex-shrink: 0;
  border-radius: 4px;
}

.side-foot {
  font-size: 11px;
  color: var(--faint);
  padding-top: 10px;
  letter-spacing: 0.4px;
  border-top: 1px solid var(--border);
  margin-top: 10px;
}

.no-results {
  color: var(--faint);
  font-size: 13px;
  padding: 12px 8px;
  text-align: center;
}

/* ==========================================================================
   Main Content Column & Topbar
   ========================================================================== */

#main {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
}

#topbar {
  position: sticky;
  top: 0;
  z-index: 25;
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 28px;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  font-size: 13px;
  color: var(--muted);
  min-height: 48px;
}

/* ==========================================================================
   Home Landing Page Full-Width Mode (body.is-landing)
   ========================================================================== */

.landing-brand, .landing-nav { display: none; }
.theme-toggle-btn {
  background: var(--panel);
  color: var(--muted);
  border: 1px solid var(--border);
  border-radius: 8px;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 15px;
  transition: all 0.15s ease;
}
.theme-toggle-btn:hover { color: var(--text); border-color: var(--border2); background: var(--panel2); }

body.is-landing #sidebar,
body.is-landing #pagerail,
body.is-landing #breadcrumb,
body.is-landing .topbar-actions { display: none !important; }

body.is-landing #main { width: 100%; max-width: 1060px; margin: 0 auto; min-height: 100vh; }
body.is-landing #content { padding: 20px 24px 80px; }
body.is-landing #topbar { display: flex; align-items: center; justify-content: space-between; padding: 16px 24px; border-bottom: 1px solid var(--border); background: transparent; backdrop-filter: none; }

body.is-landing .landing-brand { display: flex; align-items: center; gap: 4px; font-weight: 800; font-size: 21px; letter-spacing: -0.02em; color: var(--text); text-decoration: none; }
body.is-landing .landing-brand span { color: var(--accent); background: linear-gradient(135deg, var(--accent), #ffbe53); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
body.is-landing .landing-nav { display: flex; align-items: center; gap: 8px; }
body.is-landing .landing-nav .nav-tab-btn { padding: 6px 12px; font-size: 13px; font-weight: 600; background: var(--panel); border: 1px solid var(--border); border-radius: 8px; }
body.is-landing .landing-nav .nav-tab-btn:hover { color: var(--accent); border-color: var(--accent-border); background: var(--panel2); }

#breadcrumb {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
}

#breadcrumb a {
  color: var(--muted);
  text-decoration: none;
}

#breadcrumb a:hover {
  color: var(--text);
}

#breadcrumb b {
  color: var(--text);
  font-weight: 600;
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.global-lang-picker {
  display: flex;
  align-items: center;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 2px 3px;
  gap: 2px;
}

.lang-picker-label {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--faint);
  padding: 0 6px 0 4px;
}

.global-lang-btn {
  appearance: none;
  border: none;
  background: transparent;
  color: var(--muted);
  font: 600 11.5px/1.2 inherit;
  padding: 5px 9px;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.12s;
}

.global-lang-btn:hover {
  color: var(--text);
  background: var(--panel2);
}

.global-lang-btn.active {
  color: var(--accent);
  background: var(--accent-dim);
  font-weight: 700;
}

.timer-widget {
  display: flex;
  align-items: center;
}

#timer-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--panel);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 5px 10px;
  border-radius: 8px;
  font: 600 12px/1 inherit;
  cursor: pointer;
  transition: all 0.15s;
}

#timer-btn:hover {
  border-color: var(--accent-border);
  background: var(--panel2);
}

#timer-btn.running {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-dim);
}

#timer-display.timer-warn {
  color: var(--red);
  font-weight: 800;
  animation: pulse 1s infinite alternate;
}

@keyframes pulse {
  0% { opacity: 1; }
  100% { opacity: 0.6; }
}

#content {
  width: 100%;
  max-width: 900px;
  padding: 36px 32px 100px;
}

.loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 80px 0;
  color: var(--muted);
  gap: 14px;
  font-size: 15px;
}

.spinner {
  width: 28px;
  height: 28px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

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

/* ==========================================================================
   Page Rail (TOC)
   ========================================================================== */

#pagerail {
  width: 230px;
  min-width: 230px;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  padding: 68px 14px 24px 8px;
  font-size: 13px;
  display: none;
}

@media (min-width: 1380px) {
  #pagerail { display: block; }
}

.rail-title {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--faint);
  margin-bottom: 12px;
  padding-left: 8px;
}

#page-toc a {
  display: block;
  color: var(--muted);
  text-decoration: none;
  padding: 5px 10px;
  border-left: 2px solid var(--border);
  line-height: 1.4;
  font-size: 12.5px;
  transition: all 0.12s;
}

#page-toc a:hover {
  color: var(--text);
  border-left-color: var(--accent);
}

#page-toc a.active {
  color: var(--accent);
  border-left-color: var(--accent);
  font-weight: 600;
  background: linear-gradient(90deg, var(--accent-dim), transparent);
}

#page-toc a.lvl3 {
  padding-left: 20px;
  font-size: 12px;
}

/* ==========================================================================
   Markdown Typography & Formatting
   ========================================================================== */

#content h1 {
  font-size: 32px;
  font-weight: 800;
  line-height: 1.2;
  margin: 10px 0 10px;
  letter-spacing: -0.025em;
  color: var(--text);
}

#content h2 {
  font-size: 22px;
  font-weight: 700;
  margin: 48px 0 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
  letter-spacing: -0.015em;
  scroll-margin-top: 65px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

#content h2 .h2-min {
  font-size: 11.5px;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-dim);
  border: 1px solid var(--accent-border);
  border-radius: 99px;
  padding: 2px 10px;
  letter-spacing: 0.2px;
}

#content h3 {
  font-size: 17.5px;
  font-weight: 700;
  margin: 30px 0 12px;
  scroll-margin-top: 65px;
  color: var(--text);
}

#content h4 {
  font-size: 15px;
  font-weight: 600;
  margin: 22px 0 8px;
  color: var(--text);
}

#content p {
  margin: 12px 0;
  line-height: 1.7;
}

#content ul, #content ol {
  margin: 12px 0;
  padding-left: 24px;
}

#content li {
  margin: 6px 0;
  line-height: 1.6;
}

#content a {
  color: var(--link);
  text-decoration: none;
}

#content a:hover {
  text-decoration: underline;
}

#content hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 36px 0;
}

#content strong {
  color: var(--text);
  font-weight: 700;
}

/* ==========================================================================
   Blockquotes: Dialogues and Callouts
   ========================================================================== */

#content blockquote {
  margin: 16px 0;
  padding: 12px 18px;
  background: var(--panel);
  border-radius: 8px;
  border-left: 4px solid var(--border2);
  color: var(--text);
  font-size: 14.5px;
}

#content blockquote p {
  margin: 4px 0;
}

/* Interviewer Dialogue */
#content blockquote.dialogue-interviewer {
  background: color-mix(in srgb, var(--panel) 90%, var(--blue) 10%);
  border-left: 4px solid var(--blue);
}

/* Candidate Dialogue */
#content blockquote.dialogue-candidate {
  background: color-mix(in srgb, var(--panel) 90%, var(--accent) 10%);
  border-left: 4px solid var(--accent);
}

/* Callouts */
#content blockquote.callout-insight {
  background: color-mix(in srgb, var(--panel) 92%, var(--blue) 8%);
  border-left: 4px solid var(--blue);
}

#content blockquote.callout-trap {
  background: color-mix(in srgb, var(--panel) 92%, var(--red) 8%);
  border-left: 4px solid var(--red);
}

#content blockquote.callout-decision {
  background: color-mix(in srgb, var(--panel) 92%, var(--green) 8%);
  border-left: 4px solid var(--green);
}

/* ==========================================================================
   Tables
   ========================================================================== */

.table-wrap {
  overflow-x: auto;
  margin: 18px 0;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--panel);
  box-shadow: var(--shadow-sm);
}

#content table {
  border-collapse: collapse;
  width: 100%;
  font-size: 13.8px;
}

#content th, #content td {
  border: 1px solid var(--border);
  padding: 10px 14px;
  text-align: left;
  vertical-align: top;
}

#content th {
  background: var(--panel2);
  font-weight: 700;
  color: var(--text);
  letter-spacing: 0.2px;
}

#content tr:nth-child(even) td {
  background: color-mix(in srgb, var(--panel2) 40%, transparent);
}

/* ==========================================================================
   Code Blocks & Code Tabs
   ========================================================================== */

#content code {
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: 5px;
  padding: 2px 6px;
  font-size: 0.88em;
  font-family: ui-monospace, "JetBrains Mono", "Fira Code", "SF Mono", Menlo, Consolas, monospace;
}

.code-tabs {
  border: 1px solid var(--code-border);
  border-radius: 12px;
  margin: 20px 0;
  overflow: hidden;
  background: var(--code-bg);
  box-shadow: var(--shadow-md);
}

.tabbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--code-header);
  border-bottom: 1px solid var(--code-border);
  padding: 4px 8px;
}

.tab-group-title {
  font-size: 11.5px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.9px;
  color: var(--faint);
  padding-left: 8px;
}

.tab-btn-container {
  display: flex;
  align-items: center;
  gap: 4px;
}

.tabbar button.tab-btn {
  appearance: none;
  border: 1px solid transparent;
  background: transparent;
  color: var(--muted);
  font: 600 12.5px/1 inherit;
  padding: 7px 14px;
  border-radius: 7px;
  cursor: pointer;
  transition: all 0.12s;
}

.tabbar button.tab-btn:hover {
  color: var(--text);
  background: var(--panel);
}

.tabbar button.tab-btn.active {
  color: var(--accent);
  background: var(--panel);
  border-color: var(--border);
  font-weight: 700;
  box-shadow: var(--shadow-sm);
}

.copy-btn {
  appearance: none;
  border: 1px solid transparent;
  background: transparent;
  color: var(--muted);
  font: 500 11.5px/1 inherit;
  padding: 6px 10px;
  border-radius: 6px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 5px;
  transition: all 0.12s;
}

.copy-btn:hover {
  color: var(--text);
  background: var(--panel);
}

.copy-btn.copied {
  color: var(--green);
  font-weight: 600;
}

.code-tabs pre {
  margin: 0;
  border: none;
  border-radius: 0;
  background: transparent;
}

.code-tabs pre[hidden] {
  display: none !important;
}

pre > code {
  display: block;
  background: transparent;
  border: none;
  border-radius: 0;
  padding: 16px 20px;
  overflow-x: auto;
  font-size: 13.2px;
  line-height: 1.6;
  color: var(--code-text);
  font-family: ui-monospace, "JetBrains Mono", "Fira Code", Menlo, Monaco, Consolas, monospace;
}

/* Standalone pre */
pre[class^="language-"], pre:not(.tab-panel) {
  position: relative;
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: 12px;
  margin: 18px 0;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

pre[data-lang]::before {
  content: attr(data-lang);
  position: absolute;
  top: 8px;
  right: 12px;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  color: var(--faint);
  pointer-events: none;
}

/* Syntax Highlighting Tokens */
.tok-kw { color: var(--tok-kw); font-weight: 600; }
.tok-type { color: var(--tok-type); font-weight: 600; }
.tok-str { color: var(--tok-str); }
.tok-comm { color: var(--tok-comm); font-style: italic; }
.tok-ann { color: var(--tok-ann); font-weight: 600; }
.tok-num { color: var(--tok-num); }

/* LaTeX Math */
.katex { font-size: 1.05em; }
.katex-display {
  overflow-x: auto;
  overflow-y: hidden;
  padding: 8px 0;
  margin: 12px 0;
}

/* ==========================================================================
   Mermaid Diagrams
   ========================================================================== */

.mermaid-box {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  margin: 22px 0;
  overflow: hidden;
  box-shadow: var(--shadow-md);
  display: flex;
  flex-direction: column;
}

.mermaid-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 14px;
  background: var(--panel2);
  border-bottom: 1px solid var(--border);
}

.mermaid-head .m-title {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 11.5px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.9px;
  color: var(--accent);
}

.mermaid-body {
  padding: 24px 16px;
  display: flex;
  justify-content: center;
  overflow-x: auto;
}

.mermaid-box svg {
  max-width: 100%;
  height: auto;
}

.mermaid-error {
  color: var(--red);
  font-size: 13px;
  padding: 12px;
  background: var(--red-dim);
  border-radius: 8px;
  width: 100%;
}

.mermaid-error pre {
  white-space: pre-wrap;
  color: var(--muted);
  font-size: 12px;
  margin-top: 6px;
}

/* ==========================================================================
   Home Dashboard View
   ========================================================================== */

.hero {
  padding: 24px 0 10px;
}

.hero-badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--accent);
  background: var(--accent-dim);
  border: 1px solid var(--accent-border);
  border-radius: 99px;
  padding: 4px 12px;
  margin-bottom: 14px;
}

.hero h1 {
  font-size: 38px;
  font-weight: 800;
  margin: 0 0 12px;
  letter-spacing: -0.03em;
  line-height: 1.15;
}

.hero h1 em {
  font-style: normal;
  color: var(--accent);
  background: linear-gradient(135deg, var(--accent), #ffbf55);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero p.sub {
  color: var(--muted);
  font-size: 16.5px;
  max-width: 760px;
  line-height: 1.6;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 14px;
  margin: 26px 0 10px;
}

.stat {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 16px;
}

.stat .stat-num {
  font-size: 26px;
  font-weight: 800;
  color: var(--text);
  display: block;
  line-height: 1.1;
}

.stat .stat-lbl {
  font-size: 12px;
  font-weight: 500;
  color: var(--muted);
}

.method-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 12px;
  margin: 22px 0 10px;
}

.method-step {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 16px;
}

.method-step b {
  color: var(--accent);
  font-size: 13.5px;
  display: block;
  margin-bottom: 4px;
}

.method-step span {
  font-size: 12.8px;
  color: var(--muted);
  line-height: 1.45;
  display: block;
}

/* Portal Track Hub Cards */
.portal-tracks {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 20px;
  margin: 28px 0 40px;
}

.portal-track-card {
  position: relative;
  display: flex;
  flex-direction: column;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
  text-decoration: none;
  color: var(--text);
  transition: all 0.2s ease;
  box-shadow: var(--shadow-sm);
}

.portal-track-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
}

.portal-track-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.portal-track-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  background: var(--panel2);
  border: 1px solid var(--border);
}

.portal-track-title {
  font-size: 19px;
  font-weight: 700;
  color: var(--text);
  margin: 0;
}

.portal-track-desc {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.55;
  margin-bottom: 20px;
  flex: 1;
}

.portal-track-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 14px;
  border-top: 1px solid var(--border);
  font-size: 13px;
  color: var(--faint);
}

.portal-track-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--accent);
}

.home-group-title {
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.4px;
  color: var(--faint);
  margin: 40px 0 16px;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(265px, 1fr));
  gap: 16px;
}

.card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 18px 18px 16px;
  text-decoration: none;
  color: var(--text);
  transition: transform 0.15s ease, border-color 0.15s ease, box-shadow 0.15s ease;
}

.card:hover {
  transform: translateY(-3px);
  border-color: var(--accent-border);
  box-shadow: var(--shadow-md);
}

.card h3 {
  margin: 0;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.35;
  padding-right: 28px;
}

.card .blurb {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.5;
  flex: 1;
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 4px;
}

.chip {
  font-size: 11px;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 99px;
  border: 1px solid var(--border2);
  color: var(--muted);
  white-space: nowrap;
}

.chip.d-Easy { color: var(--green); border-color: var(--green-dim); background: var(--green-dim); }
.chip.d-Medium { color: var(--yellow); border-color: var(--yellow-dim); background: var(--yellow-dim); }
.chip.d-Hard { color: var(--red); border-color: var(--red-dim); background: var(--red-dim); }
.chip.d-Guide { color: var(--blue); border-color: var(--blue-dim); background: var(--blue-dim); }
.chip.chip-pat { background: var(--panel2); }

.card.is-done {
  border-color: rgba(16, 185, 129, 0.35);
}

.card.is-done:hover {
  border-color: #10b981;
}

.card-done-badge {
  position: absolute;
  top: 14px;
  right: 14px;
  font-size: 11px;
  font-weight: 700;
  color: #10b981;
  background: rgba(16, 185, 129, 0.12);
  border: 1px solid rgba(16, 185, 129, 0.3);
  padding: 2px 7px;
  border-radius: 99px;
  letter-spacing: 0.02em;
}

/* ==========================================================================
   Page Footer Nav
   ========================================================================== */

.pager {
  display: flex;
  gap: 14px;
  margin-top: 56px;
}

.pager a {
  flex: 1;
  text-decoration: none;
  color: var(--text);
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 18px;
  transition: all 0.15s;
}

.pager a:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.pager a.next {
  text-align: right;
}

.pager .dir {
  font-size: 11px;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 1px;
  display: block;
  margin-bottom: 2px;
}

.pager .pt {
  font-size: 14.5px;
  font-weight: 600;
}

.mark-done-row {
  margin-top: 24px;
  text-align: center;
}

.mark-done-row button {
  appearance: none;
  cursor: pointer;
  font: 600 13px/1 inherit;
  color: var(--text);
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 99px;
  padding: 10px 22px;
  transition: all 0.15s;
}

.mark-done-row button:hover {
  border-color: var(--accent);
}

.mark-done-row button.done {
  color: #0b0e14;
  background: var(--accent);
  border-color: var(--accent);
  font-weight: 700;
}

/* ==========================================================================
   Scrollbar & Responsive Breakpoints
   ========================================================================== */

::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-thumb {
  background: var(--border2);
  border-radius: 8px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--muted);
}

::-webkit-scrollbar-track {
  background: transparent;
}

@media print {
  #sidebar, #pagerail, #topbar, .pager, .mark-done-row, .copy-btn, .tabbar, .global-lang-picker, .timer-widget {
    display: none !important;
  }
  #content {
    max-width: 100%;
    padding: 0;
  }
  body {
    background: #fff;
    color: #000;
  }
}

@media (max-width: 960px) {
  #app { flex-direction: column; }
  #sidebar {
    position: static;
    width: 100%;
    min-width: 0;
    height: auto;
    max-height: 48vh;
  }
  #content {
    padding: 24px 18px 80px;
  }
  .global-lang-picker .lang-picker-label {
    display: none;
  }
}

/* ==========================================================================
   DSA & LeetCode Directory & View Switcher
   ========================================================================== */

.nav-tabs-switcher {
  display: flex;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 9px;
  padding: 3px;
  margin-bottom: 12px;
  gap: 3px;
}

.nav-tab-btn {
  flex: 1;
  text-align: center;
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
  text-decoration: none;
  padding: 6px 4px;
  border-radius: 6px;
  transition: all 0.15s ease;
  white-space: nowrap;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
}

.nav-tab-btn:hover {
  color: var(--text);
  background: var(--panel2);
}

.nav-tab-btn.active {
  color: var(--accent);
  background: var(--panel3);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

/* Quick Nav Grid */
.dsa-quick-nav {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 8px;
  margin: 16px 0 24px;
}

.dsa-quick-link {
  display: flex;
  align-items: center;
  padding: 8px 12px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  text-decoration: none;
  font-size: 13px;
  font-weight: 500;
  transition: all 0.15s ease;
}

.dsa-quick-link:hover {
  border-color: var(--accent-border);
  background: var(--panel2);
  color: var(--accent);
  transform: translateY(-1px);
}

/* Actionable LeetCode Problem Table */
.dsa-table-wrap {
  width: 100%;
  overflow-x: auto;
  margin: 14px 0 28px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--panel);
  box-shadow: var(--shadow-sm);
}

.dsa-table-wrap table {
  width: 100%;
  border-collapse: collapse;
  margin: 0;
}

.dsa-table-wrap th {
  background: var(--panel2);
  color: var(--faint);
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  text-align: left;
  white-space: nowrap;
}

.dsa-table-wrap td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  font-size: 13.5px;
  vertical-align: middle;
}

.dsa-table-wrap tr:last-child td {
  border-bottom: none;
}

.dsa-table-wrap tr:hover td {
  background: var(--panel2);
}

.dsa-table-wrap tr.row-done td {
  opacity: 0.6;
}

.dsa-table-wrap tr.row-done td.col-problem a {
  text-decoration: line-through;
}

.dsa-table-checkbox {
  width: 16px;
  height: 16px;
  accent-color: var(--accent);
  cursor: pointer;
  vertical-align: middle;
}

.col-check {
  width: 40px;
  text-align: center;
}

.col-problem {
  font-weight: 600;
  white-space: nowrap;
}

.col-problem a {
  color: var(--link);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.col-problem a:hover {
  text-decoration: underline;
}

.col-problem a .ext-icon {
  font-size: 11px;
  color: var(--faint);
}

.col-diff {
  width: 80px;
  text-align: center;
}

.diff-badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 99px;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  color: var(--b-col, var(--text));
  background: color-mix(in srgb, var(--b-col) 14%, transparent);
  border: 1px solid color-mix(in srgb, var(--b-col) 30%, transparent);
}
.diff-badge.diff-easy { --b-col: #10b981; }
.diff-badge.diff-medium { --b-col: #f59e0b; }
.diff-badge.diff-hard { --b-col: #f43f5e; }

.col-concept {
  color: var(--muted);
  line-height: 1.5;
  min-width: 260px;
}

.dsa-comp-subtext {
  display: block;
  margin-top: 7px;
  font-size: 0.75em; /* 25% smaller than concept font size */
  color: var(--accent);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  letter-spacing: 0.02em;
  opacity: 0.92;
}

.col-origin {
  white-space: nowrap;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 12px;
  color: var(--faint);
  width: 140px;
}

/* Sidebar Topic Item Styling */
.dsa-topic-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 10px;
  border-radius: 6px;
  color: var(--muted);
  text-decoration: none;
  font-size: 13px;
  font-weight: 500;
  margin-bottom: 2px;
  transition: all 0.15s ease;
}

.dsa-topic-item:hover {
  color: var(--text);
  background: var(--panel);
}

.dsa-topic-item.active {
  color: var(--accent);
  background: var(--panel2);
  font-weight: 600;
}

.dsa-topic-count {
  font-size: 11px;
  color: var(--faint);
  background: var(--panel2);
  padding: 1px 6px;
  border-radius: 99px;
  border: 1px solid var(--border);
}