:root {
      --bg-page: #f8fafc;
      --bg-surface: #ffffff;
      --bg-subtle: #f1f5f9;
      --bg-indigo-soft: #eef2ff;
      --bg-amber-soft: #fffbeb;
      --bg-rose-soft: #fff1f2;
      --bg-emerald-soft: #ecfdf5;
      --text-main: #0f172a;
      --text-body: #1e293b;
      --text-muted: #64748b;
      --border-light: #e2e8f0;
      --brand-navy: #1e3a8a;
      --brand-blue: #2563eb;
      --brand-saffron: #c2410c;
      --brand-amber: #d97706;
      --brand-emerald: #059669;
      --brand-rose: #e11d48;
      --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.06);
      --shadow-md: 0 6px 20px -2px rgba(15, 23, 42, 0.07);
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --reading-size: 17px;
    }

    body[data-reader-theme="sepia"] {
      --bg-page: #f4ecd8;
      --bg-surface: #fdf8eb;
      --bg-subtle: #ebe0c5;
      --bg-indigo-soft: #e6dac0;
      --bg-amber-soft: #f5e6c8;
      --bg-rose-soft: #f3d9d4;
      --bg-emerald-soft: #dce8d6;
      --text-main: #291f1a;
      --text-body: #3d2f28;
      --text-muted: #6e5a4f;
      --border-light: #d6c6a9;
      --brand-navy: #7c2d12;
      --brand-blue: #9a3412;
    }

    body[data-reader-theme="dark"] {
      --bg-page: #0b1120;
      --bg-surface: #111827;
      --bg-subtle: #1e293b;
      --bg-indigo-soft: #1e293b;
      --bg-amber-soft: #291d0a;
      --bg-rose-soft: #2c1219;
      --bg-emerald-soft: #09221b;
      --text-main: #f8fafc;
      --text-body: #e2e8f0;
      --text-muted: #94a3b8;
      --border-light: #1f2937;
      --brand-navy: #60a5fa;
      --brand-blue: #3b82f6;
      --brand-saffron: #fb923c;
    }

    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }

    body {
      font-family: 'Noto Sans Devanagari', 'Inter', 'Nirmala UI', system-ui, sans-serif;
      background-color: var(--bg-page);
      color: var(--text-body);
      line-height: 1.85;
      transition: background-color 0.2s ease, color 0.2s ease;
    }

    /* Top Reading Progress Bar */
    .reading-progress-wrap {
      position: fixed;
      top: 0;
      left: 0;
      right: 0;
      height: 4px;
      background: rgba(148, 163, 184, 0.2);
      z-index: 999;
    }

    .reading-progress-bar {
      height: 100%;
      width: 0%;
      background: linear-gradient(90deg, #2563eb, #ea580c, #059669);
      transition: width 0.1s linear;
    }

    /* Reader controls */
.reader-tools-strip{background:var(--bg-surface);border-bottom:1px solid var(--border-light)}
.reader-tools-inner{max-width:1340px;margin:0 auto;padding:.65rem 1.25rem;display:flex;justify-content:flex-end;align-items:center;gap:.4rem;flex-wrap:wrap}
.reader-controls{display:flex;align-items:center;gap:.4rem;flex-wrap:wrap}
.ctrl-btn{background:var(--bg-subtle);color:var(--text-body);border:1px solid var(--border-light);padding:.34rem .68rem;border-radius:7px;font-size:.78rem;font-weight:700;cursor:pointer;font-family:inherit;transition:all .15s}
.ctrl-btn:hover,.ctrl-btn.active{background:var(--brand-navy);color:#fff;border-color:var(--brand-navy)}
/* Chapter Hero Header */
    .chapter-hero {
      background: linear-gradient(135deg, #0f172a 0%, #1e3a8a 60%, #1e40af 100%);
      color: #ffffff;
      padding: 2.25rem 1.25rem 2rem;
      border-bottom: 4px solid #ea580c;
    }

    .hero-container {
      max-width: 1340px;
      margin: 0 auto;
    }

    .breadcrumbs {
      font-size: 0.82rem;
      color: #cbd5e1;
      margin-bottom: 0.85rem;
      display: flex;
      flex-wrap: wrap;
      gap: 0.4rem;
      align-items: center;
    }

    .breadcrumbs a {
      color: #93c5fd;
      text-decoration: none;
    }

    .hero-badges {
      display: flex;
      flex-wrap: wrap;
      gap: 0.5rem;
      margin-bottom: 0.85rem;
    }

    .hero-badge {
      font-size: 0.75rem;
      font-weight: 700;
      padding: 0.22rem 0.7rem;
      border-radius: 999px;
      background: rgba(255, 255, 255, 0.14);
      border: 1px solid rgba(255, 255, 255, 0.25);
    }

    .hero-badge.saffron {
      background: rgba(234, 88, 12, 0.25);
      border-color: #fb923c;
      color: #ffedd5;
    }

    .chapter-hero h1 {
      font-size: 2rem;
      font-weight: 800;
      line-height: 1.35;
      margin-bottom: 0.5rem;
    }

    .chapter-hero .en-subtitle {
      font-size: 1.05rem;
      color: #bfdbfe;
      font-weight: 500;
      margin-bottom: 1.15rem;
    }

    .hero-meta-strip {
      display: flex;
      flex-wrap: wrap;
      gap: 1.25rem;
      font-size: 0.84rem;
      color: #e2e8f0;
      padding-top: 0.9rem;
      border-top: 1px solid rgba(255, 255, 255, 0.15);
    }

    /* Main 2-Column Layout */
    .layout-grid {
      max-width: 1340px;
      margin: 0 auto;
      padding: 1.75rem 1.25rem 4rem;
      display: grid;
      grid-template-columns: 300px minmax(0, 1fr);
      gap: 2rem;
      align-items: start;
    }

    /* Left Sticky Sidebar (TOC + Quick Facts) */
    .sticky-sidebar {
      position: sticky;
      top: 74px;
      display: flex;
      flex-direction: column;
      gap: 1.15rem;
      max-height: calc(100vh - 90px);
      overflow-y: auto;
      scrollbar-width: thin;
    }

    .sidebar-card {
      background: var(--bg-surface);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 1.15rem;
      box-shadow: var(--shadow-sm);
    }

    .sidebar-title {
      font-size: 0.9rem;
      font-weight: 800;
      color: var(--brand-navy);
      margin-bottom: 0.75rem;
      padding-bottom: 0.5rem;
      border-bottom: 2px solid var(--border-light);
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    .toc-list {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 0.3rem;
    }

    .toc-link {
      display: block;
      padding: 0.45rem 0.65rem;
      border-radius: 6px;
      font-size: 0.83rem;
      font-weight: 600;
      color: var(--text-body);
      text-decoration: none;
      border-left: 3px solid transparent;
      transition: all 0.15s;
      line-height: 1.4;
    }

    .toc-link:hover, .toc-link.active {
      background: var(--bg-indigo-soft);
      color: var(--brand-blue);
      border-left-color: var(--brand-blue);
    }

    .quick-fact-row {
      display: flex;
      justify-content: space-between;
      font-size: 0.8rem;
      padding: 0.4rem 0;
      border-bottom: 1px dashed var(--border-light);
    }

    .quick-fact-row:last-child {
      border-bottom: none;
    }

    .quick-fact-val {
      font-weight: 700;
      color: var(--brand-saffron);
    }

    /* Main Reading Column */
    .reading-canvas {
      font-size: var(--reading-size);
      display: flex;
      flex-direction: column;
      gap: 1.75rem;
    }

    /* Exam Synopsis / At-a-Glance Box */
    .synopsis-banner {
      background: linear-gradient(135deg, var(--bg-indigo-soft), var(--bg-surface));
      border: 1px solid var(--border-light);
      border-left: 5px solid var(--brand-blue);
      border-radius: var(--radius-md);
      padding: 1.35rem 1.5rem;
      box-shadow: var(--shadow-sm);
    }

    .synopsis-banner h2 {
      font-size: 1.1rem;
      color: var(--brand-navy);
      margin-bottom: 0.5rem;
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }

    .synopsis-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
      gap: 0.85rem;
      margin-top: 0.85rem;
    }

    .synopsis-pill {
      background: var(--bg-surface);
      border: 1px solid var(--border-light);
      padding: 0.75rem 0.9rem;
      border-radius: var(--radius-sm);
      font-size: 0.86rem;
    }

    /* Section Card Styling */
    .chapter-section {
      background: var(--bg-surface);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-lg);
      padding: 1.85rem 2rem;
      box-shadow: var(--shadow-md);
      scroll-margin-top: 84px;
    }

    .sec-header {
      display: flex;
      align-items: center;
      gap: 0.85rem;
      margin-bottom: 1.25rem;
      padding-bottom: 0.85rem;
      border-bottom: 2px solid var(--border-light);
    }

    .sec-num {
      width: 38px;
      height: 38px;
      border-radius: 10px;
      background: var(--brand-navy);
      color: #ffffff;
      font-weight: 800;
      font-size: 1.05rem;
      display: flex;
      align-items: center;
      justify-content: center;
      flex-shrink: 0;
    }

    .sec-title-wrap h2 {
      font-size: 1.35rem;
      font-weight: 800;
      color: var(--text-main);
      line-height: 1.3;
    }

    .sec-title-wrap .sec-en {
      font-size: 0.84rem;
      color: var(--text-muted);
      font-weight: 600;
    }

    /* Sub-cards & Two-Column Concept Grids */
    .two-col-cards {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(310px, 1fr));
      gap: 1.15rem;
      margin: 1rem 0;
    }

    .three-col-cards {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
      gap: 1rem;
      margin: 1rem 0;
    }

    .concept-card {
      background: var(--bg-subtle);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 1.2rem 1.3rem;
      transition: transform 0.15s;
    }

    .concept-card.border-blue { border-top: 4px solid var(--brand-blue); }
    .concept-card.border-saffron { border-top: 4px solid var(--brand-saffron); }
    .concept-card.border-emerald { border-top: 4px solid var(--brand-emerald); }
    .concept-card.border-amber { border-top: 4px solid var(--brand-amber); }

    .concept-card h3 {
      font-size: 1.05rem;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 0.55rem;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    .concept-list {
      padding-left: 1.2rem;
      font-size: 0.94rem;
    }

    .concept-list li {
      margin-bottom: 0.45rem;
    }

    /* Key Highlight Term */
    mark.exam-hl {
      background: rgba(245, 158, 11, 0.22);
      color: inherit;
      padding: 0.05rem 0.35rem;
      border-radius: 4px;
      font-weight: 700;
    }

    .metric-badge {
      display: inline-block;
      font-size: 0.78rem;
      font-weight: 700;
      background: var(--bg-indigo-soft);
      color: var(--brand-blue);
      padding: 0.12rem 0.5rem;
      border-radius: 6px;
      border: 1px solid rgba(37, 99, 235, 0.2);
    }

    /* Interactive SVG Diagram Container */
    .diagram-box {
      background: var(--bg-subtle);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 1.25rem;
      margin: 1.25rem 0;
      text-align: center;
    }

    .diagram-caption {
      font-size: 0.84rem;
      color: var(--text-muted);
      margin-top: 0.65rem;
      font-weight: 600;
    }

    /* Styled Comparison Table */
    .table-container {
      overflow-x: auto;
      margin: 1.15rem 0;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-light);
    }

    table.geo-table {
      width: 100%;
      border-collapse: collapse;
      font-size: 0.92rem;
      background: var(--bg-surface);
    }

    table.geo-table th {
      background: var(--brand-navy);
      color: #ffffff;
      text-align: left;
      padding: 0.8rem 1rem;
      font-weight: 700;
    }

    table.geo-table td {
      padding: 0.8rem 1rem;
      border-bottom: 1px solid var(--border-light);
      vertical-align: top;
    }

    table.geo-table tr:nth-child(even) td {
      background: var(--bg-subtle);
    }

    /* Mnemonic / Memory Trick Box */
    .mnemonic-box {
      background: var(--bg-emerald-soft);
      border: 1px solid rgba(5, 150, 105, 0.35);
      border-left: 5px solid var(--brand-emerald);
      border-radius: var(--radius-md);
      padding: 1rem 1.25rem;
      margin-top: 1rem;
      font-size: 0.93rem;
    }

    /* Prelims Trap & Mains Framework Boxes */
    .prelims-trap-box {
      background: var(--bg-rose-soft);
      border: 1px solid rgba(225, 29, 72, 0.3);
      border-left: 5px solid var(--brand-rose);
      border-radius: var(--radius-md);
      padding: 1.25rem 1.4rem;
      margin-bottom: 1.25rem;
    }

    .prelims-trap-box h3 {
      color: var(--brand-rose);
      font-size: 1.08rem;
      margin-bottom: 0.6rem;
      display: flex;
      align-items: center;
      gap: 0.45rem;
    }

    .mains-framework-box {
      background: var(--bg-amber-soft);
      border: 1px solid rgba(217, 119, 6, 0.35);
      border-left: 5px solid var(--brand-amber);
      border-radius: var(--radius-md);
      padding: 1.25rem 1.4rem;
    }

    .mains-framework-box h3 {
      color: var(--brand-saffron);
      font-size: 1.08rem;
      margin-bottom: 0.6rem;
    }

    /* Elemental Bar Chart */
    .bar-row {
      margin-bottom: 0.65rem;
    }

    .bar-label {
      display: flex;
      justify-content: space-between;
      font-size: 0.86rem;
      font-weight: 700;
      margin-bottom: 0.2rem;
    }

    .bar-track {
      height: 10px;
      background: var(--border-light);
      border-radius: 999px;
      overflow: hidden;
    }

    .bar-fill {
      height: 100%;
      border-radius: 999px;
    }

    /* Interactive Quiz Cards */
    .quiz-option {
      display: block;
      width: 100%;
      text-align: left;
      padding: 0.7rem 1rem;
      margin-top: 0.45rem;
      border-radius: 8px;
      border: 1.5px solid var(--border-light);
      background: var(--bg-surface);
      color: var(--text-body);
      font-family: inherit;
      font-size: 0.9rem;
      cursor: pointer;
      transition: all 0.15s;
    }

    .quiz-option:hover {
      border-color: var(--brand-blue);
      background: var(--bg-indigo-soft);
    }

    .quiz-option.correct {
      background: var(--bg-emerald-soft);
      border-color: var(--brand-emerald);
      color: var(--brand-emerald);
      font-weight: 700;
    }

    .quiz-option.wrong {
      background: var(--bg-rose-soft);
      border-color: var(--brand-rose);
      color: var(--brand-rose);
    }

    .quiz-exp {
      display: none;
      margin-top: 0.6rem;
      padding: 0.75rem 1rem;
      background: var(--bg-emerald-soft);
      border-radius: 8px;
      font-size: 0.86rem;
      border-left: 3px solid var(--brand-emerald);
    }

    @media (max-width: 980px) {
      .layout-grid {
        grid-template-columns: 1fr;
      }
      .sticky-sidebar {
        position: static;
        max-height: none;
      }
      .chapter-section {
        padding: 1.35rem 1.2rem;
      }
      .chapter-hero h1 {
        font-size: 1.55rem;
      }
    }
/* UPSCStudy production integration */
body.geo-chapter-template{margin:0;background:var(--bg-page);color:var(--text-body)}
body.geo-chapter-template .as-header,body.geo-chapter-template .as-footer{font-size:16px}
body.geo-chapter-template .chapter-hero{margin-top:0}
.toc-panel{padding:0;overflow:hidden}
.toc-panel>summary{list-style:none;cursor:pointer;padding:1.15rem}
.toc-panel>summary::-webkit-details-marker{display:none}
.toc-panel .toc-list{padding:0 1.15rem 1.15rem}
.toc-chevron{font-size:.78rem;color:var(--text-muted);transition:transform .2s ease}
.toc-panel[open] .toc-chevron{transform:rotate(180deg)}
.quick-facts-card{overflow:hidden}
.chapter-bottom-nav{display:flex;justify-content:space-between;gap:1rem;align-items:center;padding:1rem 0 .25rem;font-size:.9rem;color:var(--text-muted)}
.chapter-bottom-nav a{color:var(--brand-blue);font-weight:800;text-decoration:none}
.chapter-bottom-nav a:hover{text-decoration:underline}
@media(max-width:980px){
 .reader-tools-inner{justify-content:flex-start;padding:.55rem .8rem}
 .reader-tools-inner .ctrl-btn{font-size:.74rem;padding:.32rem .55rem}
 .layout-grid{padding:1rem .75rem 3rem;gap:1rem}
 .sticky-sidebar{gap:.75rem}
 .quick-facts-card{display:none}
 .toc-panel{max-height:none}
 .toc-panel:not([open]) .toc-list{display:none}
 .toc-panel>summary{padding:.85rem 1rem}
 .chapter-hero{padding:1.45rem .9rem 1.25rem}
 .hero-meta-strip{gap:.55rem;font-size:.78rem}
 .chapter-section{border-radius:12px;box-shadow:var(--shadow-sm)}
 .two-col-cards,.three-col-cards{grid-template-columns:1fr}
 .table-container{margin-left:-.2rem;margin-right:-.2rem}
}
@media(max-width:560px){
 .chapter-hero h1{font-size:1.42rem}
 .chapter-hero .en-subtitle{font-size:.9rem}
 .hero-badges{gap:.35rem}
 .hero-badge{font-size:.68rem;padding:.18rem .5rem}
 .reading-canvas{gap:1rem}
 .chapter-section{padding:1.1rem .95rem}
 .sec-header{align-items:flex-start;gap:.65rem}
 .sec-num{width:34px;height:34px;font-size:.95rem}
 .sec-title-wrap h2{font-size:1.16rem}
 .synopsis-banner{padding:1rem}
 table.geo-table{min-width:680px}
 .chapter-bottom-nav{flex-direction:column;align-items:flex-start}
}

/* Geomorphology shared visual adapters — extracted from chapter pages */
/* Extracted visual rules: geography/geomorphology/continental-drift-seafloor-spreading/index.html */
.chapter2-bank-section{position:relative}
.chapter2-bank-section>div.flex:first-child{display:flex;align-items:flex-start;justify-content:space-between;gap:1rem;flex-wrap:wrap;margin-bottom:1rem;padding-bottom:.85rem;border-bottom:2px solid var(--border-light)}
.chapter2-bank-section>div.flex:first-child>div{min-width:0;flex:1}
.chapter2-bank-section h2{font-size:1.35rem;font-weight:800;color:var(--text-main);line-height:1.35;margin:0}
.chapter2-bank-section h2+ p{margin-top:.45rem;color:var(--text-muted);font-size:.9rem;line-height:1.65}
.chapter2-bank-section>div.flex:first-child>span{font-size:.75rem;font-weight:800;padding:.25rem .65rem;border-radius:999px;background:var(--bg-indigo-soft);color:var(--brand-blue);white-space:nowrap}
#sec-5 .grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,300px),1fr));gap:1rem}
#sec-5 .grid>div{background:var(--bg-rose-soft);border:1px solid rgba(225,29,72,.28);border-left:5px solid var(--brand-rose);border-radius:var(--radius-md);padding:1rem 1.15rem;line-height:1.8}
#sec-5 .grid>div>strong{color:var(--brand-rose)}
#sec-5 h2{margin-bottom:.45rem}
#sec-6 details,#sec-7 details{border:1px solid var(--border-light);border-radius:var(--radius-md);overflow:hidden;background:var(--bg-surface);margin-top:.9rem}
#sec-6 details[open],#sec-7 details[open]{box-shadow:var(--shadow-sm)}
#sec-6 summary,#sec-7 summary{cursor:pointer;list-style:none;padding:1rem 1.15rem;background:var(--bg-subtle);font-weight:800;color:var(--text-main);display:flex;align-items:flex-start;justify-content:space-between;gap:1rem;line-height:1.55}
#sec-6 summary::-webkit-details-marker,#sec-7 summary::-webkit-details-marker{display:none}
#sec-6 summary>span:last-child,#sec-7 summary>span:last-child{color:var(--brand-blue);font-size:.9rem}
#sec-6 details>div,#sec-7 details>div{border-top:1px solid var(--border-light)!important;background:var(--bg-surface)!important}
#sec-6 .whitespace-pre-line,#sec-7 .whitespace-pre-line{white-space:pre-line!important;padding:1.15rem 1.25rem!important;font-size:.95rem!important;line-height:1.9!important;color:var(--text-body)!important}
#sec-7 .space-y-3{display:flex;flex-direction:column;gap:.9rem}
#sec-6 .text-violet-700,#sec-7 .text-emerald-700{display:inline-block;color:var(--brand-blue)!important;font-size:.78rem;font-weight:800;margin-bottom:.2rem}
#sec-7 .text-emerald-700{color:var(--brand-emerald)!important}
#sec-6 .bg-violet-100,#sec-7 .bg-emerald-100{background:var(--bg-indigo-soft)!important;color:var(--brand-blue)!important}
@media(max-width:680px){
  .chapter2-bank-section{padding:1.25rem 1rem}
  .chapter2-bank-section h2{font-size:1.18rem}
  #sec-6 summary,#sec-7 summary{padding:.9rem 1rem;font-size:.93rem}
  #sec-6 .whitespace-pre-line,#sec-7 .whitespace-pre-line{padding:1rem!important;font-size:.93rem!important;line-height:1.82!important}
}

/* Extracted visual rules: geography/geomorphology/earth-interior-seismic-waves/index.html */
.chapter1-bank>div.bank-head{display:flex;align-items:flex-start;justify-content:space-between;gap:1rem;flex-wrap:wrap;margin-bottom:1rem;padding-bottom:.85rem;border-bottom:2px solid var(--border-light)}
.chapter1-bank>div.bank-head>div{min-width:0;flex:1}
.chapter1-bank h2{font-size:1.35rem;font-weight:800;color:var(--text-main);line-height:1.35;margin:0}
.chapter1-bank .bank-sub{margin-top:.45rem;color:var(--text-muted);font-size:.9rem;line-height:1.65}
.chapter1-bank .bank-count{font-size:.75rem;font-weight:800;padding:.25rem .65rem;border-radius:999px;background:var(--bg-indigo-soft);color:var(--brand-blue);white-space:nowrap}
.chapter1-bank details{border:1px solid var(--border-light);border-radius:var(--radius-md);overflow:hidden;background:var(--bg-surface);margin-top:.9rem}
.chapter1-bank details[open]{box-shadow:var(--shadow-sm)}
.chapter1-bank summary{cursor:pointer;list-style:none;padding:1rem 1.15rem;background:var(--bg-subtle);font-weight:800;color:var(--text-main);display:flex;align-items:flex-start;justify-content:space-between;gap:1rem;line-height:1.55}
.chapter1-bank summary::-webkit-details-marker{display:none}
.chapter1-bank summary .tag{display:inline-block;color:var(--brand-blue);font-size:.78rem;font-weight:800;margin-bottom:.25rem}
.chapter1-bank details .answer{white-space:pre-line;padding:1.15rem 1.25rem;font-size:.95rem;line-height:1.9;color:var(--text-body);border-top:1px solid var(--border-light)}
.chapter1-bank .answer strong{color:var(--text-main)}
#sec-10 summary .tag{color:var(--brand-emerald)}
#sec-10 details .answer{background:var(--bg-surface)}
@media(max-width:680px){
 .chapter1-bank{padding:1.25rem 1rem}
 .chapter1-bank h2{font-size:1.18rem}
 .chapter1-bank summary{padding:.9rem 1rem;font-size:.93rem}
 .chapter1-bank details .answer{padding:1rem;font-size:.93rem;line-height:1.82}
}

/* Extracted visual rules: geography/geomorphology/earthquakes-tsunami/index.html */
.chapter5-source{overflow:hidden}
.chapter5-source>p,.chapter5-source>div,.chapter5-source>ul,.chapter5-source>ol{max-width:100%}
.chapter5-source img{display:block;max-width:100%;height:auto;margin-inline:auto}
.chapter5-source figure{max-width:100%}
.chapter5-source table{width:100%;border-collapse:collapse}
.chapter5-source th,.chapter5-source td{vertical-align:top}
.chapter5-source .text-xs{line-height:1.65}
.chapter5-source .text-sm{line-height:1.75}
.chapter5-source .leading-relaxed{line-height:1.85}
.chapter5-source .overflow-x-auto{max-width:100%;overflow-x:auto}
.chapter5-source [class*="grid-cols-"]{min-width:0}
.chapter5-source .bg-white{background:var(--bg-surface)!important}
.chapter5-source .bg-slate-50,.chapter5-source .bg-slate-50\/70{background:var(--bg-subtle)!important}
.chapter5-source .text-slate-900{color:var(--text-main)!important}
.chapter5-source .text-slate-800,.chapter5-source .text-slate-700,.chapter5-source .text-slate-600{color:var(--text-body)!important}
.chapter5-source .border-slate-200{border-color:var(--border-light)!important}
.chapter5-source .muted-text{color:var(--text-muted)!important}
.chapter5-source details{margin-top:.8rem}
.chapter5-source .sec-header+*{margin-top:0}
.chapter5-source .sec-header h2{margin:0!important;padding:0!important;border:0!important}
.chapter5-source .sec-header{position:relative;z-index:2}
.chapter4-quiz-card{background:var(--bg-subtle);padding:1.15rem;border-radius:10px;border:1px solid var(--border-light)}
@media(max-width:680px){
  .chapter5-source{padding:1.2rem 1rem}
  .chapter5-source table{font-size:.82rem}
  .chapter5-source th,.chapter5-source td{padding:.65rem!important}
}

/* Extracted visual rules: geography/geomorphology/earthquakes-tsunami/index.html */
.chapter5-source{min-width:0}
.chapter5-source .code-diagram{font-family:"Courier New",Courier,monospace;line-height:1.45}
.chapter5-source img{display:block;max-width:100%;height:auto;margin-inline:auto}
.chapter5-source figure{max-width:100%}
.chapter5-source article{scroll-margin-top:128px}
.chapter5-source table{width:100%;border-collapse:collapse}
.chapter5-source .overflow-x-auto{max-width:100%;overflow-x:auto;-webkit-overflow-scrolling:touch}
.chapter5-source .card-surface{background:var(--bg-surface)!important;color:var(--text-body)}
.chapter5-source .sub-surface{color:var(--text-body)}
.chapter5-source .text-slate-900{color:var(--text-main)!important}
.chapter5-source .text-slate-800,.chapter5-source .text-slate-700,.chapter5-source .text-slate-600{color:var(--text-body)!important}
.chapter5-source .border-slate-200{border-color:var(--border-light)!important}
.chapter5-source .muted-text{color:var(--text-muted)!important}
[data-theme="dark"] .chapter5-source .bg-white{background:var(--bg-surface)!important}
[data-theme="dark"] .chapter5-source .bg-slate-50,
[data-theme="dark"] .chapter5-source .bg-slate-50\/50,
[data-theme="dark"] .chapter5-source .bg-slate-50\/70,
[data-theme="dark"] .chapter5-source .bg-slate-100{background:var(--bg-subtle)!important}
[data-theme="dark"] .chapter5-source table thead{background:#334155!important;color:#f8fafc!important}
@media(max-width:680px){
  .chapter5-source article{padding:1.05rem!important}
  .chapter5-source table{font-size:.78rem}
  .chapter5-source th,.chapter5-source td{padding:.55rem!important}
}

/* Extracted visual rules: geography/geomorphology/earthquakes-tsunami/index.html */
.chapter5-source{min-width:0}
.chapter5-source img{display:block;max-width:100%;height:auto;margin-inline:auto}
.chapter5-source figure{max-width:100%}
.chapter5-source article{scroll-margin-top:128px}
.chapter5-source table{width:100%;border-collapse:collapse}
.chapter5-source .overflow-x-auto{max-width:100%;overflow-x:auto;-webkit-overflow-scrolling:touch}
.chapter5-source .card-surface{background:var(--bg-surface)!important;color:var(--text-body)}
.chapter5-source .text-slate-900{color:var(--text-main)!important}
.chapter5-source .text-slate-800,.chapter5-source .text-slate-700,.chapter5-source .text-slate-600{color:var(--text-body)!important}
.chapter5-source .border-slate-200{border-color:var(--border-light)!important}
[data-theme="dark"] .chapter5-source .bg-white{background:var(--bg-surface)!important}
[data-theme="dark"] .chapter5-source .bg-slate-50,
[data-theme="dark"] .chapter5-source .bg-slate-50\/50,
[data-theme="dark"] .chapter5-source .bg-slate-50\/70,
[data-theme="dark"] .chapter5-source .bg-slate-100{background:var(--bg-subtle)!important}
[data-theme="dark"] .chapter5-source table thead{background:#334155!important;color:#f8fafc!important}
@media(max-width:680px){
  .chapter5-source article{padding:1.05rem!important}
  .chapter5-source table{font-size:.78rem}
  .chapter5-source th,.chapter5-source td{padding:.55rem!important}
}

/* Extracted visual rules: geography/geomorphology/plate-tectonics-mountain-building/index.html */
.chapter3-source{overflow:hidden}
.chapter3-source>p,.chapter3-source>div,.chapter3-source>ul,.chapter3-source>ol{max-width:100%}
.chapter3-source img{display:block;max-width:100%;height:auto;margin-inline:auto}
.chapter3-source figure{max-width:100%}
.chapter3-source table{width:100%;border-collapse:collapse}
.chapter3-source th,.chapter3-source td{vertical-align:top}
.chapter3-source .text-xs{line-height:1.65}
.chapter3-source .text-sm{line-height:1.75}
.chapter3-source .leading-relaxed{line-height:1.85}
.chapter3-source .overflow-x-auto{max-width:100%;overflow-x:auto}
.chapter3-source [class*="grid-cols-"]{min-width:0}
.chapter3-source .bg-white{background:var(--bg-surface)!important}
.chapter3-source .bg-slate-50,.chapter3-source .bg-slate-50\/70{background:var(--bg-subtle)!important}
.chapter3-source .text-slate-900{color:var(--text-main)!important}
.chapter3-source .text-slate-800,.chapter3-source .text-slate-700,.chapter3-source .text-slate-600{color:var(--text-body)!important}
.chapter3-source .border-slate-200{border-color:var(--border-light)!important}
.chapter3-source .muted-text{color:var(--text-muted)!important}
.chapter3-source details{margin-top:.8rem}
.chapter3-source .sec-header+*{margin-top:0}
.chapter3-source .sec-header h2{margin:0!important;padding:0!important;border:0!important}
.chapter3-source .sec-header{position:relative;z-index:2}
.chapter3-quiz-card{background:var(--bg-subtle);padding:1.15rem;border-radius:10px;border:1px solid var(--border-light)}
@media(max-width:680px){
  .chapter3-source{padding:1.2rem 1rem}
  .chapter3-source table{font-size:.82rem}
  .chapter3-source th,.chapter3-source td{padding:.65rem!important}
}

/* Extracted visual rules: geography/geomorphology/rocks-folding-faulting/index.html */
.chapter6-source{overflow:hidden}
.chapter6-source>p,.chapter6-source>div,.chapter6-source>ul,.chapter6-source>ol{max-width:100%}
.chapter6-source img{display:block;max-width:100%;height:auto;margin-inline:auto}
.chapter6-source figure{max-width:100%}
.chapter6-source table{width:100%;border-collapse:collapse}
.chapter6-source th,.chapter6-source td{vertical-align:top}
.chapter6-source .text-xs{line-height:1.65}
.chapter6-source .text-sm{line-height:1.75}
.chapter6-source .leading-relaxed{line-height:1.85}
.chapter6-source .overflow-x-auto{max-width:100%;overflow-x:auto}
.chapter6-source [class*="grid-cols-"]{min-width:0}
.chapter6-source .bg-white{background:var(--bg-surface)!important}
.chapter6-source .bg-slate-50,.chapter6-source .bg-slate-50\/70{background:var(--bg-subtle)!important}
.chapter6-source .text-slate-900{color:var(--text-main)!important}
.chapter6-source .text-slate-800,.chapter6-source .text-slate-700,.chapter6-source .text-slate-600{color:var(--text-body)!important}
.chapter6-source .border-slate-200{border-color:var(--border-light)!important}
.chapter6-source .muted-text{color:var(--text-muted)!important}
.chapter6-source details{margin-top:.8rem}
.chapter6-source .sec-header+*{margin-top:0}
.chapter6-source .sec-header h2{margin:0!important;padding:0!important;border:0!important}
.chapter6-source .sec-header{position:relative;z-index:2}
.chapter4-quiz-card{background:var(--bg-subtle);padding:1.15rem;border-radius:10px;border:1px solid var(--border-light)}
@media(max-width:680px){
  .chapter6-source{padding:1.2rem 1rem}
  .chapter6-source table{font-size:.82rem}
  .chapter6-source th,.chapter6-source td{padding:.65rem!important}
}

/* Extracted visual rules: geography/geomorphology/rocks-folding-faulting/index.html */
.chapter6-source{min-width:0}
.chapter6-source .code-diagram{font-family:"Courier New",Courier,monospace;line-height:1.45}
.chapter6-source img{display:block;max-width:100%;height:auto;margin-inline:auto}
.chapter6-source figure{max-width:100%}
.chapter6-source article{scroll-margin-top:128px}
.chapter6-source table{width:100%;border-collapse:collapse}
.chapter6-source .overflow-x-auto{max-width:100%;overflow-x:auto;-webkit-overflow-scrolling:touch}
.chapter6-source .card-surface{background:var(--bg-surface)!important;color:var(--text-body)}
.chapter6-source .sub-surface{color:var(--text-body)}
.chapter6-source .text-slate-900{color:var(--text-main)!important}
.chapter6-source .text-slate-800,.chapter6-source .text-slate-700,.chapter6-source .text-slate-600{color:var(--text-body)!important}
.chapter6-source .border-slate-200{border-color:var(--border-light)!important}
.chapter6-source .muted-text{color:var(--text-muted)!important}
[data-theme="dark"] .chapter6-source .bg-white{background:var(--bg-surface)!important}
[data-theme="dark"] .chapter6-source .bg-slate-50,
[data-theme="dark"] .chapter6-source .bg-slate-50\/50,
[data-theme="dark"] .chapter6-source .bg-slate-50\/70,
[data-theme="dark"] .chapter6-source .bg-slate-100{background:var(--bg-subtle)!important}
[data-theme="dark"] .chapter6-source table thead{background:#334155!important;color:#f8fafc!important}
@media(max-width:680px){
  .chapter6-source article{padding:1.05rem!important}
  .chapter6-source table{font-size:.78rem}
  .chapter6-source th,.chapter6-source td{padding:.55rem!important}
}

/* Extracted visual rules: geography/geomorphology/rocks-folding-faulting/index.html */
.chapter6-source{min-width:0}
.chapter6-source img{display:block;max-width:100%;height:auto;margin-inline:auto}
.chapter6-source figure{max-width:100%}
.chapter6-source article{scroll-margin-top:128px}
.chapter6-source table{width:100%;border-collapse:collapse}
.chapter6-source .overflow-x-auto{max-width:100%;overflow-x:auto;-webkit-overflow-scrolling:touch}
.chapter6-source .card-surface{background:var(--bg-surface)!important;color:var(--text-body)}
.chapter6-source .text-slate-900{color:var(--text-main)!important}
.chapter6-source .text-slate-800,.chapter6-source .text-slate-700,.chapter6-source .text-slate-600{color:var(--text-body)!important}
.chapter6-source .border-slate-200{border-color:var(--border-light)!important}
[data-theme="dark"] .chapter6-source .bg-white{background:var(--bg-surface)!important}
[data-theme="dark"] .chapter6-source .bg-slate-50,
[data-theme="dark"] .chapter6-source .bg-slate-50\/50,
[data-theme="dark"] .chapter6-source .bg-slate-50\/70,
[data-theme="dark"] .chapter6-source .bg-slate-100{background:var(--bg-subtle)!important}
[data-theme="dark"] .chapter6-source table thead{background:#334155!important;color:#f8fafc!important}
@media(max-width:680px){
  .chapter6-source article{padding:1.05rem!important}
  .chapter6-source table{font-size:.78rem}
  .chapter6-source th,.chapter6-source td{padding:.55rem!important}
}

/* Extracted visual rules: geography/geomorphology/volcanism-volcanic-landforms/index.html */
.chapter4-source{overflow:hidden}
.chapter4-source>p,.chapter4-source>div,.chapter4-source>ul,.chapter4-source>ol{max-width:100%}
.chapter4-source img{display:block;max-width:100%;height:auto;margin-inline:auto}
.chapter4-source figure{max-width:100%}
.chapter4-source table{width:100%;border-collapse:collapse}
.chapter4-source th,.chapter4-source td{vertical-align:top}
.chapter4-source .text-xs{line-height:1.65}
.chapter4-source .text-sm{line-height:1.75}
.chapter4-source .leading-relaxed{line-height:1.85}
.chapter4-source .overflow-x-auto{max-width:100%;overflow-x:auto}
.chapter4-source [class*="grid-cols-"]{min-width:0}
.chapter4-source .bg-white{background:var(--bg-surface)!important}
.chapter4-source .bg-slate-50,.chapter4-source .bg-slate-50\/70{background:var(--bg-subtle)!important}
.chapter4-source .text-slate-900{color:var(--text-main)!important}
.chapter4-source .text-slate-800,.chapter4-source .text-slate-700,.chapter4-source .text-slate-600{color:var(--text-body)!important}
.chapter4-source .border-slate-200{border-color:var(--border-light)!important}
.chapter4-source .muted-text{color:var(--text-muted)!important}
.chapter4-source details{margin-top:.8rem}
.chapter4-source .sec-header+*{margin-top:0}
.chapter4-source .sec-header h2{margin:0!important;padding:0!important;border:0!important}
.chapter4-source .sec-header{position:relative;z-index:2}
.chapter4-quiz-card{background:var(--bg-subtle);padding:1.15rem;border-radius:10px;border:1px solid var(--border-light)}
@media(max-width:680px){
  .chapter4-source{padding:1.2rem 1rem}
  .chapter4-source table{font-size:.82rem}
  .chapter4-source th,.chapter4-source td{padding:.65rem!important}
}

/* Extracted visual rules: geography/geomorphology/volcanism-volcanic-landforms/index.html */
.chapter4-source{min-width:0}
.chapter4-source .code-diagram{font-family:"Courier New",Courier,monospace;line-height:1.45}
.chapter4-source img{display:block;max-width:100%;height:auto;margin-inline:auto}
.chapter4-source figure{max-width:100%}
.chapter4-source article{scroll-margin-top:128px}
.chapter4-source table{width:100%;border-collapse:collapse}
.chapter4-source .overflow-x-auto{max-width:100%;overflow-x:auto;-webkit-overflow-scrolling:touch}
.chapter4-source .card-surface{background:var(--bg-surface)!important;color:var(--text-body)}
.chapter4-source .sub-surface{color:var(--text-body)}
.chapter4-source .text-slate-900{color:var(--text-main)!important}
.chapter4-source .text-slate-800,.chapter4-source .text-slate-700,.chapter4-source .text-slate-600{color:var(--text-body)!important}
.chapter4-source .border-slate-200{border-color:var(--border-light)!important}
.chapter4-source .muted-text{color:var(--text-muted)!important}
[data-theme="dark"] .chapter4-source .bg-white{background:var(--bg-surface)!important}
[data-theme="dark"] .chapter4-source .bg-slate-50,
[data-theme="dark"] .chapter4-source .bg-slate-50\/50,
[data-theme="dark"] .chapter4-source .bg-slate-50\/70,
[data-theme="dark"] .chapter4-source .bg-slate-100{background:var(--bg-subtle)!important}
[data-theme="dark"] .chapter4-source table thead{background:#334155!important;color:#f8fafc!important}
@media(max-width:680px){
  .chapter4-source article{padding:1.05rem!important}
  .chapter4-source table{font-size:.78rem}
  .chapter4-source th,.chapter4-source td{padding:.55rem!important}
}

/* Shared chapter navigation */
.chapter-nav{display:flex;gap:1rem;justify-content:space-between;flex-wrap:wrap;margin:1.5rem 0 2rem}
.chapter-nav .ctrl-btn{display:inline-flex;align-items:center;text-decoration:none}
@media(max-width:760px){.chapter-nav{flex-direction:column}.chapter-nav .ctrl-btn{width:100%;justify-content:center;text-align:center}}