:root {
            --navy: #1B2A4A;
            --navy-light: #25396B;
            --teal: #00A896;
            --teal-light: #00D4BE;
            --orange: #FF7B2A;
            --orange-light: #FF9F5A;
            --yellow: #FFC857;
            --green: #2ECC71;
            --green-light: #58E694;
            --cream: #FDF6E3;
            --cream-dark: #F5ECDB;
            --white: #FFFFFF;
            --ink: #2C3E50;
            --ink-soft: #5A6B7F;
            --sidebar-width: 280px;
            --toc-width: 280px;
            --card-radius: 16px;
            --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
        }

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

        body {
            background-color: var(--cream);
            color: var(--ink);
            font-family: 'Inter', sans-serif;
            line-height: 1.7;
            min-height: 100vh;
            display: flex; flex-direction: column;
        }

        .site-layout {
            display: grid;
            grid-template-columns: var(--toc-width) minmax(0, 1fr) var(--sidebar-width);
            justify-content: center;
            align-items: start;
            gap: 1.5rem;
            flex: 1;
            padding: 2rem;
            max-width: 1500px;
            margin: 0 auto;
            width: 100%;
        }

        .doc-content { min-width: 0; width: 100%; }

        .section-badge {
            display: inline-flex; align-items: center; gap: 0.5rem;
            background: linear-gradient(135deg, var(--navy) 0%, var(--navy-light) 100%);
            color: var(--white); padding: 0.6rem 1.2rem;
            border-radius: 50px; font-size: 1rem; font-weight: 600;
            margin-bottom: 1.5rem; box-shadow: 0 4px 20px rgba(27, 42, 74, 0.3);
            border: none;
        }
        .section-badge a { color: var(--white); text-decoration: none; border-bottom: 1px dashed var(--teal-light); transition: var(--transition); }
        .section-badge a:hover { border-bottom-color: var(--yellow); color: var(--yellow); }

        .content-card {
            background: var(--white); border-radius: var(--card-radius);
            padding: 2.5rem; margin: 1.5rem 0;
            border: 1px solid rgba(27,42,74,0.06);
            box-shadow: 0 2px 12px rgba(27,42,74,0.04);
        }

        h1, h2, h3, h4, h5, h6 {
            font-family: 'Crimson Pro', serif; font-weight: 700; color: var(--navy);
            margin-top: 2.5rem; margin-bottom: 1.25rem; line-height: 1.3;
            position: relative; padding-left: 1rem;
        }
        h1 { font-size: 2.5rem; border-bottom: 3px solid var(--teal); padding-bottom: 0.75rem; padding-left: 0; }
        h1::before { content: ""; position: absolute; left: -1rem; top: 0.2rem; bottom: 0.2rem; width: 6px; background: linear-gradient(180deg, var(--teal), var(--orange)); border-radius: 3px; }
        h2 { font-size: 2rem; color: var(--navy); border-left: 4px solid var(--orange); padding-left: 1rem; background: linear-gradient(90deg, rgba(255,123,42,0.05), transparent); border-radius: 0 8px 8px 0; scroll-margin-top: 2rem; }
        h3 { font-size: 1.6rem; color: var(--navy-light); border-left: 3px solid var(--teal); padding-left: 0.85rem; }
        h4 { font-size: 1.35rem; color: var(--ink); }

        p { margin-bottom: 1.25rem; font-size: 1.1rem; color: var(--ink); }
        .lead { font-size: 1.25rem; color: var(--navy-light); font-weight: 500; margin-bottom: 1.5rem; }

        .highlight { background: linear-gradient(120deg, var(--yellow), var(--orange-light)); color: var(--navy); padding: 0.2rem 0.5rem; border-radius: 4px; font-weight: 600; }

        blockquote {
            border-left: 4px solid var(--teal);
            background: linear-gradient(90deg, rgba(0,168,150,0.08), transparent);
            padding: 1.5rem 2rem; margin: 1.5rem 0;
            border-radius: 0 12px 12px 0;
            font-style: italic; color: var(--ink-soft);
            position: relative; overflow: hidden;
        }
        blockquote::before {
            content: "\201D"; font-family: 'Crimson Pro', serif;
            font-size: 4rem; color: var(--teal); opacity: 0.15;
            position: absolute; top: -1rem; left: 1rem;
        }

        ul, ol { margin-bottom: 1.25rem; padding-left: 1.75rem; }
        li { margin-bottom: 0.5rem; }

        table {
            width: 100%;
            border-collapse: separate;
            border-spacing: 0;
            margin: 1.5rem 0;
            font-size: 0.95rem;
        }
        th {
            background: linear-gradient(135deg, var(--navy) 0%, var(--navy-light) 100%);
            color: var(--white);
            font-weight: 600;
            padding: 0.85rem 1.5rem;
            text-align: left;
            border: none;
        }
        td {
            padding: 0.75rem 1.5rem;
            border-bottom: 1px solid rgba(27, 42, 74, 0.1);
            color: var(--ink);
        }
        tr:last-child td {
            border-bottom: none;
        }
        tbody tr:hover td {
            background: rgba(0, 168, 150, 0.04);
        }
        thead th:first-child { border-radius: 8px 0 0 0; }
        thead th:last-child { border-radius: 0 8px 0 0; }
        ul li::marker { color: var(--teal); font-weight: 700; }
        ol { counter-reset: item; list-style: none; padding-left: 1.5rem; }
        ol li { position: relative; padding-left: 2rem; }
        ol li::before {
            counter-increment: item; content: counter(item) ".";
            position: absolute; left: 0; top: 0;
            color: var(--orange); font-weight: 700; font-family: 'Crimson Pro', serif;
        }

        .section-rule { border: none; border-top: 2px dashed rgba(27,42,74,0.15); margin: 2rem 0; }

        a { color: var(--teal); text-decoration: none; border-bottom: 1px dashed var(--teal-light); transition: var(--transition); }
        a:hover { border-bottom-color: var(--orange); color: var(--orange); }
        
        /* External links — open in new tab */
        a[href^="http"] { 
            background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2300A896' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M18 13v6a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2h6'/%3E%3Cpolyline points='15 3 21 3 21 9'/%3E%3Cline x1='10' y1='14' x2='21' y2='3'/%3E%3C/svg%3E");
            background-repeat: no-repeat;
            background-position: right center;
            padding-right: 16px;
        }
        a[href^="http"]:hover {
            background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23FF7B2A' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M18 13v6a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2h6'/%3E%3Cpolyline points='15 3 21 3 21 9'/%3E%3Cline x1='10' y1='14' x2='21' y2='3'/%3E%3C/svg%3E");
        }

        .citation { font-family: 'Inter', sans-serif; font-size: 0.9em; color: var(--ink-soft); background: rgba(0,168,150,0.1); padding: 0.15rem 0.4rem; border-radius: 4px; }

        .callout {
            border-radius: 12px; padding: 1.5rem; margin: 1.5rem 0;
            border-left: 5px solid; display: flex; gap: 1rem; align-items: flex-start;
        }
        .callout-tip { background: linear-gradient(90deg, rgba(0,168,150,0.1), transparent); border-color: var(--teal); }
        .callout-tip::before { content: "💡"; font-size: 1.5rem; }
        .callout-warning { background: linear-gradient(90deg, rgba(255,123,42,0.1), transparent); border-color: var(--orange); }
        .callout-warning::before { content: "⚠️"; font-size: 1.5rem; }
        .callout-note { background: linear-gradient(90deg, rgba(27,42,74,0.08), transparent); border-color: var(--navy); }
        .callout-note::before { content: "📝"; font-size: 1.5rem; }
        .callout-example { background: linear-gradient(90deg, rgba(255,200,87,0.15), transparent); border-color: var(--yellow); }
        .callout-example::before { content: "🎯"; font-size: 1.5rem; }

        .card-grid {
            display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 1.5rem; margin: 2rem 0;
        }
        .topic-card {
            background: var(--white); border-radius: 14px; padding: 1.5rem;
            border: 1px solid rgba(27,42,74,0.08);
            transition: var(--transition); text-decoration: none; color: inherit; display: block;
        }
        .topic-card:hover { transform: translateY(-4px); box-shadow: 0 12px 32px rgba(27,42,74,0.12); border-color: var(--teal); }
        .topic-card .card-icon { font-size: 2.5rem; margin-bottom: 0.75rem; display: block; }
        .topic-card h3 { margin: 0 0 0.5rem; font-size: 1.25rem; }
        .topic-card p { margin: 0; font-size: 0.95rem; color: var(--ink-soft); font-size: 0.95rem; }

        .progress-bar {
            height: 6px; background: rgba(27,42,74,0.1); border-radius: 3px; overflow: hidden; margin: 1rem 0;
        }
        .progress-bar-fill {
            height: 100%; background: linear-gradient(90deg, var(--teal), var(--orange));
            border-radius: 3px; transition: width 0.5s ease;
        }

        .site-footer {
            width: 100%; padding: 2rem; border-top: 1px solid rgba(27,42,74,0.1);
            color: var(--ink-soft); font-size: 0.9rem;
            text-align: center; background: var(--cream-dark);
            margin-top: 3rem;
        }

        .paper-meta {
            display: flex; flex-wrap: wrap; gap: 1rem; margin: 1.5rem 0;
            padding: 1.5rem; background: linear-gradient(135deg, var(--navy) 0%, var(--navy-light) 100%);
            border-radius: var(--card-radius); color: var(--white);
        }
        .paper-meta-item { display: flex; align-items: center; gap: 0.5rem; font-size: 0.95rem; }
        .paper-meta-item::before { font-size: 1.2rem; }

        .toc-expand { background: none; border: none; color: var(--ink-soft); font: inherit; cursor: pointer; padding: 0; font-size: 0.9rem; display: flex; align-items: center; gap: 0.35rem; transition: var(--transition); }
        .toc-expand:hover { color: var(--teal); }
        .toc-expand svg { transition: transform 0.2s; }
        .toc-expand[aria-expanded="true"] svg { transform: rotate(180deg); }

        /* Code blocks */
        pre { background: var(--navy); color: var(--cream); padding: 1.5rem; border-radius: 10px; overflow-x: auto; margin: 1.5rem 0; }
        code { font-family: 'Fira Code', 'Consolas', monospace; font-size: 0.9em; }
        .highlight { background: linear-gradient(120deg, var(--yellow), var(--orange-light)); color: var(--navy); padding: 0.2rem 0.5rem; border-radius: 4px; font-weight: 600; }

        .card-grid {
            display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 1.5rem; margin: 2rem 0;
        }
        .topic-card {
            background: var(--white); border-radius: 14px; padding: 1.5rem;
            border: 1px solid rgba(27,42,74,0.08);
            transition: var(--transition); text-decoration: none; color: inherit; display: block;
        }
        .topic-card:hover { transform: translateY(-4px); box-shadow: 0 12px 32px rgba(27,42,74,0.12); border-color: var(--teal); }
        .topic-card .card-icon { font-size: 2.5rem; margin-bottom: 0.75rem; display: block; }
        .topic-card h3 { margin: 0 0 0.5rem; font-size: 1.25rem; }
        .topic-card p { margin: 0; font-size: 0.95rem; color: var(--ink-soft); font-size: 0.95rem; }

        .progress-bar {
            height: 6px; background: rgba(27,42,74,0.1); border-radius: 3px; overflow: hidden; margin: 1rem 0;
        }
        .progress-bar-fill {
            height: 100%; background: linear-gradient(90deg, var(--teal), var(--orange));
            border-radius: 3px; transition: width 0.5s ease;
        }

        .site-footer {
            width: 100%; padding: 2rem; border-top: 1px solid rgba(27,42,74,0.1);
            color: var(--ink-soft); font-size: 0.9rem;
            text-align: center; background: var(--cream-dark);
            margin-top: 3rem;
        }

        .paper-meta {
            display: flex; flex-wrap: wrap; gap: 1rem; margin: 1.5rem 0;
            padding: 1.5rem; background: linear-gradient(135deg, var(--navy) 0%, var(--navy-light) 100%);
            border-radius: var(--card-radius); color: var(--white);
        }
        .paper-meta-item { display: flex; align-items: center; gap: 0.5rem; font-size: 0.95rem; }
        .paper-meta-item::before { font-size: 1.2rem; }

        .toc-expand { background: none; border: none; color: var(--ink-soft); font: inherit; cursor: pointer; padding: 0; font-size: 0.9rem; display: flex; align-items: center; gap: 0.35rem; transition: var(--transition); }
        .toc-expand:hover { color: var(--teal); }
        .toc-expand svg { transition: transform 0.2s; }
        .toc-expand[aria-expanded="true"] svg { transform: rotate(180deg); }

        @media (max-width: 1000px) {
            .site-layout { grid-template-columns: 1fr; gap: 1rem; padding: 1rem; }
            .toc-panel, .doc-nav { width: 100%; position: static; max-height: none; }
            .doc-nav { order: 3; }
            .toc-panel { order: 1; }
            .doc-content { order: 2; }
        }
        
        @media (max-width: 700px) {
            .site-layout { padding: 0.75rem; }
            .toc-panel, .doc-nav { padding: 1rem; }
            .doc-nav ul { display: none; }
            .doc-nav .nav-toggle { display: block; }
        }

        /* ===== Breadcrumbs ===== */
        .breadcrumbs {
            display: flex;
            align-items: center;
            gap: 0.5rem;
            margin-bottom: 1rem;
            padding: 0.5rem 0;
            font-size: 0.875rem;
            color: var(--ink-soft);
            flex-wrap: wrap;
        }
        .breadcrumbs a {
            color: var(--teal);
            text-decoration: none;
            border-bottom: 1px dashed var(--teal-light);
            transition: var(--transition);
        }
        .breadcrumbs a:hover {
            color: var(--orange);
            border-bottom-color: var(--orange);
        }
        .breadcrumbs .separator {
            color: var(--ink-soft);
            opacity: 0.5;
        }
        .breadcrumbs .current {
            color: var(--ink);
            font-weight: 500;
        }
        .breadcrumbs .home-icon {
            font-size: 1rem;
            line-height: 1;
        }

        /* ===== Tabbed Code Blocks ===== */
        .code-tabs {
            margin: 1.5rem 0;
            border-radius: var(--card-radius);
            overflow: hidden;
            border: 1px solid rgba(27, 42, 74, 0.1);
            background: var(--white);
        }
        .code-tabs-nav {
            display: flex;
            background: linear-gradient(135deg, var(--navy) 0%, var(--navy-light) 100%);
            border-bottom: 1px solid rgba(27, 42, 74, 0.15);
        }
        .code-tab-btn {
            flex: 1;
            padding: 0.85rem 1.25rem;
            border: none;
            background: transparent;
            color: var(--cream);
            font: inherit;
            font-weight: 500;
            font-size: 0.875rem;
            cursor: pointer;
            transition: var(--transition);
            border-bottom: 3px solid transparent;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 0.5rem;
        }
        .code-tab-btn:hover {
            background: rgba(255, 255, 255, 0.08);
        }
        .code-tab-btn.active {
            background: var(--white);
            color: var(--navy);
            border-bottom-color: var(--teal);
        }
        .code-tab-btn::before {
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.8rem;
        }
        .code-tab-btn[data-lang="python"]::before { content: "🐍"; }
        .code-tab-btn[data-lang="cpp"]::before { content: "⚡"; }
        .code-tab-btn[data-lang="java"]::before { content: "☕"; }
        .code-tab-btn[data-lang="csharp"]::before { content: "🔷"; }
        .code-tab-btn[data-lang="ruby"]::before { content: "💎"; }
        .code-tab-panel {
            display: none;
            padding: 1.25rem;
        }
        .code-tab-panel.active {
            display: block;
            animation: fadeIn 0.2s ease;
        }
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(4px); }
            to { opacity: 1; transform: translateY(0); }
        }
        .code-tab-panel pre {
            margin: 0;
            border-radius: 6px;
            overflow-x: auto;
        }
        .code-tab-panel code {
            font-family: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
            font-size: 0.875rem;
            line-height: 1.6;
        }
        /* Prism toolbar position fix */
        .code-tab-panel .prism-toolbar {
            position: static;
            opacity: 1;
        }
        .code-tab-panel button.copy-to-clipboard {
            background: var(--navy);
            color: var(--cream);
            border: none;
            padding: 0.35rem 0.75rem;
            border-radius: 4px;
            font-size: 0.75rem;
            cursor: pointer;
            transition: var(--transition);
        }
        .code-tab-panel button.copy-to-clipboard:hover {
            background: var(--teal);
        }

/* ---- Additions: references, citations, listing cards, prev/next (build.py) ---- */
a.citation {
    font-size: 0.8em; vertical-align: super; line-height: 1;
    border-bottom: none; padding: 0 0.1rem;
}
ol.references { padding-left: 2rem; font-size: 0.95rem; }
ol.references li { margin-bottom: 0.75rem; line-height: 1.55; scroll-margin-top: 2rem; }
ol.references li:target { background-color: var(--yellow, #FFC857); border-radius: 6px; padding: 0.3rem 0.5rem; }
ol.references a { word-break: break-all; font-size: 0.9em; }

.topic-articles { display: flex; flex-direction: column; gap: 1rem; }
.topic-article-card {
    background: var(--white, #fff); border: 1px solid rgba(27,42,74,0.15);
    border-radius: 12px; padding: 1.25rem 1.5rem;
    transition: border-color 0.2s, box-shadow 0.2s;
    position: relative;
}
/* stretch the title link over the whole card so it acts as one button */
.topic-article-card h3 a::after { content: ""; position: absolute; inset: 0; }
.topic-article-card:hover { border-color: var(--teal, #00A896); box-shadow: 0 4px 12px rgba(27,42,74,0.10); }
.topic-article-card h3 { margin: 0 0 0.35rem 0; font-size: 1.2rem; background: none; border: none; padding: 0; position: static; }
.topic-article-card p { margin: 0; font-size: 0.95rem; }

.related-block {
    background: var(--cream, #F5ECDB); border: 1px solid rgba(27,42,74,0.15);
    border-radius: 12px; padding: 1.25rem 1.5rem; margin: 2rem 0;
}
.related-block h2 { margin-top: 0; font-size: 1.3rem; }
.related-block ul { margin: 0.75rem 0 0; padding-left: 1.25rem; }

.page-siblings { display: flex; justify-content: space-between; gap: 1rem; margin: 2.5rem 0 1rem; font-size: 0.95rem; }
.page-siblings a {
    display: inline-block; padding: 0.6rem 1rem; background: var(--white, #fff);
    border: 1px solid rgba(27,42,74,0.15); border-radius: 10px; max-width: 46%;
}
.page-siblings a:hover { border-color: var(--teal, #00A896); }
.page-siblings .next { margin-left: auto; text-align: right; }


/* ---- Panel tint for the shared panels.css ---- */
:root {
    --panel-width: var(--toc-width, 280px);
    --panel-bg-a: #FFFFFF;
    --panel-bg-b: var(--cream-dark, #F0E6CE);
    --panel-border: rgba(27, 42, 74, 0.08);
    --panel-shadow: rgba(27, 42, 74, 0.06);
    --panel-heading-font: 'Crimson Pro', serif;
    --panel-heading-color: var(--navy);
    --panel-accent: var(--teal);
    --panel-fg: var(--navy);
    --panel-fg-soft: var(--ink-soft, #5A6B7F);
    --panel-btn-a: var(--navy);
    --panel-btn-b: var(--navy-light);
    --panel-btn-fg: #FFFFFF;
    --panel-chevron-bg: var(--teal);
    --panel-chevron-fg: #FFFFFF;
    --panel-hover: rgba(0, 168, 150, 0.15);
    --panel-active-a: rgba(0, 168, 150, 0.2);
    --panel-active-b: rgba(255, 123, 42, 0.1);
    --panel-active-accent: var(--orange);
}