/* ===== Design Tokens ===== */
:root {
    --bg: #0d0d12;
    --sidebar-bg: #111118;
    --article-bg: #111118;
    --border: rgba(255, 255, 255, 0.07);
    --text: #e2e2e8;
    --text-secondary: #909099;
    --text-muted: #4a4a5a;
    --brand: #10b981;
    --brand-dim: rgba(16, 185, 129, 0.1);
    --brand-border: rgba(16, 185, 129, 0.25);
    --accent: #f59e0b;
    --font-display: "Space Grotesk", "Noto Sans SC", sans-serif;
    --font-body: "Noto Sans SC", "Inter", sans-serif;
    --font-mono: "JetBrains Mono", "Fira Code", monospace;
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; }

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
}

body {
    margin: 0;
    font-family: var(--font-body);
    font-size: 15px;
    color: var(--text);
    background: var(--bg);
    overflow-x: hidden;
}

a { color: var(--brand); text-decoration: none; }
a:hover { color: #34d399; }
code, pre { font-family: var(--font-mono); }

/* ===== Shell ===== */
.site-shell {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ===== Header ===== */
.doc-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(13, 13, 18, 0.92);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
}

.doc-header-inner,
.doc-footer {
    width: min(1360px, calc(100% - 48px));
    margin: 0 auto;
}

.doc-header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    padding: 13px 0;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    color: var(--text);
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1rem;
    letter-spacing: -0.02em;
}

.brand:hover { opacity: 0.8; color: var(--text); }

.brand-logo { width: 28px; height: 28px; }

.brand-text {
    background: linear-gradient(135deg, var(--text) 40%, var(--brand));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.doc-nav { display: flex; gap: 2px; }

.doc-nav a {
    color: var(--text-secondary);
    font-size: 0.82rem;
    padding: 5px 10px;
    border-radius: 6px;
    transition: color 0.15s, background 0.15s;
}

.doc-nav a:hover { color: var(--text); background: rgba(255,255,255,0.05); }
.doc-nav a.is-active { color: var(--text); }

.nav-friend-link {
    color: #818cf8 !important;
    border: 1px solid rgba(129, 140, 248, 0.3);
    margin-left: 6px;
    font-size: 0.76rem !important;
    padding: 4px 9px !important;
}

.nav-friend-link:hover {
    color: #14b8a6 !important;
    background: rgba(129, 140, 248, 0.08) !important;
    border-color: #14b8a6 !important;
}

/* ===== 3-Column Main Layout ===== */
.doc-main {
    display: grid;
    grid-template-columns: 232px minmax(0, 1fr) 192px;
    gap: 0;
    width: min(1360px, calc(100% - 48px));
    margin: 0 auto;
    padding: 24px 0 64px;
    align-items: start;
}

/* ===== Left Sidebar ===== */
.doc-sidebar {
    position: sticky;
    top: 57px;
    max-height: calc(100vh - 70px);
    overflow-y: auto;
    padding: 20px 16px 20px 0;
    border-right: 1px solid var(--border);
    scrollbar-width: thin;
    scrollbar-color: rgba(255,255,255,0.06) transparent;
}

.doc-sidebar::-webkit-scrollbar { width: 3px; }
.doc-sidebar::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.06); border-radius: 2px; }

.sidebar-label {
    margin: 0 0 10px 8px;
    color: var(--text-muted);
    font-size: 0.65rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

/* Module accordion (JS-driven, no <details>) */
.nav-module { margin-bottom: 1px; }

.nav-module-row {
    display: flex;
    align-items: center;
    gap: 2px;
}

.nav-toggle-btn {
    flex-shrink: 0;
    width: 20px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    padding: 0;
    cursor: pointer;
    color: var(--text-muted);
    border-radius: 4px;
    transition: color 0.15s, background 0.15s;
}

.nav-toggle-btn:hover { color: var(--text-secondary); background: rgba(255,255,255,0.05); }

.nav-toggle-btn svg { transition: transform 0.18s; }

.nav-module.is-open .nav-toggle-btn svg { transform: rotate(90deg); }

.nav-toggle-gap { flex-shrink: 0; width: 20px; }

.nav-module-link {
    flex: 1;
    min-width: 0;
    padding: 5px 6px;
    border-radius: 5px;
    color: var(--text-secondary);
    font-size: 0.8rem;
    font-weight: 600;
    letter-spacing: 0.01em;
    transition: color 0.15s, background 0.15s;
    text-decoration: none;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.nav-module-link:hover { color: var(--text); background: rgba(255,255,255,0.04); }
.nav-module-link.is-active { color: var(--text); }

/* Article list inside module */
.nav-articles {
    display: none;
    padding: 3px 0 6px 0;
    margin: 2px 0 4px 9px;
    border-left: 1px solid rgba(255,255,255,0.12);
}

.nav-module.is-open .nav-articles { display: block; }

.nav-article {
    display: block;
    padding: 5px 8px 5px 12px;
    border-radius: 4px;
    color: var(--text-secondary);
    font-size: 0.775rem;
    line-height: 1.4;
    transition: color 0.15s, background 0.15s;
    text-decoration: none;
    margin-bottom: 1px;
}

.nav-article:hover {
    color: var(--text);
    background: rgba(255,255,255,0.04);
}

.nav-article.is-current {
    color: var(--brand);
    background: var(--brand-dim);
    font-weight: 500;
}

/* ===== Article (center) ===== */
.doc-article {
    padding: 36px 48px 48px;
    border-left: 1px solid var(--border);
    border-right: 1px solid var(--border);
    min-width: 0;
}

.doc-eyebrow {
    display: inline-flex;
    margin: 0 0 16px;
    padding: 4px 12px;
    border-radius: 999px;
    background: var(--brand-dim);
    border: 1px solid var(--brand-border);
    color: var(--brand);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.03em;
}

/* Article typography */
.doc-article h1,
.doc-article h2,
.doc-article h3,
.doc-article h4 {
    color: var(--text);
    letter-spacing: -0.025em;
    line-height: 1.25;
}

.doc-article h1 {
    margin: 0 0 20px;
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 700;
}

.doc-article h2 {
    margin: 44px 0 14px;
    padding-top: 20px;
    font-family: var(--font-display);
    font-size: 1.35rem;
    border-top: 1px solid var(--border);
}

.doc-article h2:first-of-type { margin-top: 32px; }

.doc-article h3 {
    margin: 28px 0 10px;
    font-size: 1.05rem;
}

.doc-article h4 {
    margin: 20px 0 8px;
    font-size: 0.95rem;
    color: var(--text-secondary);
}

.doc-article p,
.doc-article ul,
.doc-article ol,
.doc-article blockquote,
.doc-article table,
.doc-article pre,
.doc-article hr {
    margin: 0 0 18px;
}

.doc-article p,
.doc-article li {
    color: var(--text-secondary);
    font-size: 0.925rem;
    line-height: 1.85;
}

.doc-article ul,
.doc-article ol { padding-left: 22px; }
.doc-article li + li { margin-top: 6px; }

.doc-article strong { color: var(--text); font-weight: 600; }
.doc-article em { color: var(--text); }

.doc-article blockquote {
    padding: 14px 18px;
    border-left: 2px solid var(--brand);
    border-radius: 0 6px 6px 0;
    background: var(--brand-dim);
}

.doc-article blockquote p:last-child { margin-bottom: 0; }

.doc-article code {
    padding: 0.15em 0.45em;
    border-radius: 5px;
    background: rgba(255,255,255,0.07);
    color: var(--accent);
    font-size: 0.85em;
    word-break: break-word;
}

.doc-article pre {
    padding: 18px 20px;
    overflow-x: auto;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: #090910;
}

.doc-article pre code,
.doc-article pre code.hljs {
    padding: 0;
    background: transparent;
    color: #dde0ec;
    font-size: 0.84rem;
    line-height: 1.7;
}

.doc-article table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
    border: 1px solid var(--border);
    border-radius: 8px;
    overflow: hidden;
}

.doc-article th, .doc-article td { padding: 10px 14px; text-align: left; }
.doc-article th { background: rgba(255,255,255,0.04); color: var(--text); font-weight: 600; border-bottom: 1px solid var(--border); }
.doc-article td { color: var(--text-secondary); border-bottom: 1px solid rgba(255,255,255,0.03); }
.doc-article tr:last-child td { border-bottom: none; }

.doc-article hr { border: 0; border-top: 1px solid var(--border); }

.doc-article img { display: block; max-width: 100%; margin: 20px auto; border-radius: 8px; border: 1px solid var(--border); }

.doc-article a {
    color: var(--brand);
    text-decoration: underline;
    text-decoration-color: rgba(16,185,129,0.25);
    text-underline-offset: 2px;
    transition: text-decoration-color 0.15s;
}

.doc-article a:hover { text-decoration-color: var(--brand); }

/* Task lists */
.doc-article input[type="checkbox"] { width: 14px; height: 14px; margin-right: 8px; accent-color: var(--brand); }
.doc-article .task-list-item { list-style: none; margin-left: -20px; }

/* ===== Right TOC ===== */
.doc-toc {
    position: sticky;
    top: 57px;
    max-height: calc(100vh - 70px);
    overflow-y: auto;
    padding: 20px 0 20px 20px;
    border-left: 1px solid var(--border);
    scrollbar-width: thin;
    scrollbar-color: rgba(255,255,255,0.06) transparent;
}

.doc-toc::-webkit-scrollbar { width: 3px; }
.doc-toc::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.06); border-radius: 2px; }

.toc-label {
    margin: 0 0 10px;
    color: var(--text-secondary);
    font-size: 0.65rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.toc-item {
    display: block;
    padding: 4px 8px;
    border-radius: 5px;
    color: var(--text-secondary);
    font-size: 0.75rem;
    line-height: 1.4;
    text-decoration: none;
    transition: color 0.15s, background 0.15s;
    margin-bottom: 1px;
}

.toc-item:hover { color: var(--text); background: rgba(255,255,255,0.04); }

.toc-item.toc-h3 {
    padding-left: 16px;
    font-size: 0.71rem;
    color: var(--text-secondary);
    opacity: 0.75;
}

.toc-item.is-active {
    color: var(--brand);
    background: var(--brand-dim);
    opacity: 1;
}

/* ===== Footer ===== */
.doc-footer {
    margin-top: auto;
    padding: 20px 0 28px;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.78rem;
}

.doc-footer-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    flex-wrap: wrap;
}

.footer-desc {
    color: var(--text-muted);
    line-height: 1.5;
}

.footer-links {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-shrink: 0;
}

.footer-link {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.78rem;
    padding: 4px 10px;
    border: 1px solid var(--border);
    border-radius: 6px;
    transition: color 0.15s, border-color 0.15s, background 0.15s;
}

.footer-link:hover {
    color: var(--accent);
    border-color: var(--accent);
    background: rgba(16, 185, 129, 0.06);
}

/* ===== Responsive ===== */
/* Hide TOC only on narrow screens; keep it at any width where sidebar is visible */
@media (max-width: 900px) {
    .doc-main { grid-template-columns: 200px minmax(0, 1fr); }
    .doc-toc { display: none; }
    .doc-article { border-right: none; }
}

@media (max-width: 680px) {
    .doc-main { grid-template-columns: 1fr; }
    .doc-sidebar { position: static; max-height: none; overflow-y: visible; padding: 16px 0; border-right: none; }
    .doc-article { border: none; border-top: 1px solid var(--border); padding: 24px 0; }
    .doc-header-inner, .doc-main, .doc-footer { width: calc(100% - 32px); }
}

@media (max-width: 480px) {
    .doc-header-inner { flex-direction: column; align-items: flex-start; gap: 10px; }
    .doc-article h1 { font-size: 1.4rem; }
}

/* ===== Scrollbar ===== */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.08); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,0.14); }

/* ===== Mermaid Diagrams ===== */
.mermaid {
    display: flex;
    justify-content: center;
    overflow-x: auto;
    margin: 24px 0;
    padding: 24px 16px;
    background: rgba(0, 0, 0, 0.25);
    border-radius: 8px;
    border: 1px solid var(--border);
}

.mermaid svg {
    max-width: 100%;
    height: auto !important;
    font-family: var(--font-body) !important;
}

/* ===== Syntax Highlighting ===== */
.hljs { background: transparent !important; color: #dde0ec !important; }
.hljs-keyword, .hljs-selector-tag { color: #c084fc; }
.hljs-string, .hljs-addition { color: #34d399; }
.hljs-number, .hljs-literal { color: #f59e0b; }
.hljs-comment, .hljs-quote { color: #4a4a5a; font-style: italic; }
.hljs-title, .hljs-section { color: #60a5fa; }
.hljs-name, .hljs-tag { color: #f472b6; }
.hljs-attr, .hljs-attribute { color: #fbbf24; }
.hljs-built_in { color: #38bdf8; }

/* ===== Prev / Next Pager ===== */
.doc-pager {
    display: flex;
    gap: 12px;
    margin-top: 48px;
    padding-top: 28px;
    border-top: 1px solid var(--border);
}

.pager-btn {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: 14px 18px;
    border: 1px solid var(--border);
    border-radius: 10px;
    text-decoration: none !important;
    color: var(--text);
    background: rgba(255,255,255,0.02);
    transition: border-color 0.18s, background 0.18s;
    min-width: 0;
    visibility: hidden;
}

.pager-btn.is-ready { visibility: visible; }

.pager-btn:hover {
    border-color: var(--brand-border);
    background: var(--brand-dim);
    color: var(--text);
}

.pager-next { align-items: flex-end; text-align: right; }

.pager-label {
    font-size: 0.68rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-muted);
    font-family: var(--font-mono);
    transition: color 0.18s;
}

.pager-btn:hover .pager-label { color: var(--brand); }

.pager-title {
    font-size: 0.84rem;
    font-weight: 500;
    color: var(--text-secondary);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    line-height: 1.4;
    transition: color 0.18s;
}

.pager-btn:hover .pager-title { color: var(--text); }

@media (max-width: 560px) {
    .doc-pager { flex-direction: column; }
    .pager-next { align-items: flex-start; text-align: left; }
}

/* ===== Back to Top ===== */
.back-to-top {
    position: fixed;
    right: 28px;
    bottom: 72px;
    width: 42px;
    height: 42px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(13, 13, 18, 0.85);
    border: 1px solid var(--brand-border);
    border-radius: 50%;
    color: var(--brand);
    font-size: 1.15rem;
    line-height: 1;
    cursor: pointer;
    opacity: 0;
    transform: translateY(14px);
    transition: opacity 0.25s, transform 0.25s, background 0.15s, border-color 0.15s;
    z-index: 200;
    backdrop-filter: blur(8px);
    box-shadow: 0 4px 20px rgba(0,0,0,0.4);
}

.back-to-top.is-visible {
    opacity: 1;
    transform: translateY(0);
}

.back-to-top:hover {
    background: rgba(16, 185, 129, 0.15);
    border-color: var(--brand);
}

/* ===== Footer counter ===== */
.footer-counter {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    color: var(--text-muted);
    font-size: 0.74rem;
    font-family: var(--font-mono);
    padding: 3px 10px;
    border: 1px solid var(--border);
    border-radius: 6px;
    flex-shrink: 0;
}

.footer-counter .cv { color: var(--brand); font-weight: 600; }
.hljs-type, .hljs-class .hljs-title { color: #a78bfa; }
.hljs-deletion { color: #f87171; }