/* ============================================================
   科学上网手册 (ifq.homes) — original visual identity
   Format: chapter-based handbook / manual, NOT a card-grid or
   comparison-table landing page.
   Palette: warm paper/ivory background, ink-charcoal text,
   restrained burgundy-wine accent with a muted brass secondary
   tone for chapter numerals — evokes a printed manual, not a
   tech dashboard.
   (deliberately distinct from itz.mom's cream+green+orange,
   itz.lat's dark navy+cyan, and ifq.lol's light purple+coral)
   ============================================================ */

:root {
    --bg-page: #f6f1e6;
    --bg-page-alt: #efe6d2;
    --bg-card: #fffdf8;
    --bg-card-2: #faf3e4;
    --bg-panel: #f1e7d2;
    --border-color: #e0d2b0;
    --border-soft: #ead9b8;
    --primary: #7c2d3a;
    --primary-dark: #5e2029;
    --primary-rgb: 124, 45, 58;
    --primary-bright: #9c4353;
    --brass: #9c7a34;
    --brass-rgb: 156, 122, 52;
    --text-main: #2a2318;
    --text-muted: #6c6047;
    --text-soft: #9c8f70;
    --danger: #a4402f;
    --danger-rgb: 164, 64, 47;
    --good: #3f7a4f;
    --good-rgb: 63, 122, 79;
    --font-serif: "Songti SC", "Noto Serif SC", "STSong", "SimSun", "PMingLiU", Georgia, serif;
    color-scheme: light;
}

[data-theme="dark"] {
    --bg-page: #1c1710;
    --bg-page-alt: #17130d;
    --bg-card: #241d15;
    --bg-card-2: #2a2117;
    --bg-panel: #261f15;
    --border-color: #3c3122;
    --border-soft: #332a1d;
    --primary: #d9899a;
    --primary-dark: #c26a7d;
    --primary-rgb: 217, 137, 154;
    --primary-bright: #eba9b8;
    --brass: #d4af6a;
    --brass-rgb: 212, 175, 106;
    --text-main: #f1e9d9;
    --text-muted: #c7b99b;
    --text-soft: #8f8262;
    --danger: #e08672;
    --danger-rgb: 224, 134, 114;
    --good: #79c08d;
    --good-rgb: 121, 192, 141;
    color-scheme: dark;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
    background: var(--bg-page);
    color: var(--text-main);
    line-height: 1.75;
    transition: background 0.25s ease, color 0.25s ease;
}
a { text-decoration: none; color: inherit; }
ul, ol { list-style: none; }
img { max-width: 100%; }
code { background: rgba(var(--primary-rgb), 0.09); color: var(--primary-dark); padding: 2px 6px; border-radius: 4px; font-size: 0.92em; font-family: "SFMono-Regular", Consolas, monospace; }
[data-theme="dark"] code { color: var(--primary-bright); }
.container { max-width: 1140px; margin: 0 auto; padding: 0 5%; }
section { padding: 64px 5%; position: relative; }

/* Faint paper-fiber / laid-paper texture, fixed on page */
body::before {
    content: "";
    position: fixed;
    inset: 0;
    z-index: 0;
    pointer-events: none;
    background-image:
        repeating-linear-gradient(180deg, rgba(var(--brass-rgb), 0.05) 0px, transparent 1px, transparent 3px),
        radial-gradient(circle at 12% 4%, rgba(var(--primary-rgb), 0.06) 0%, transparent 46%),
        radial-gradient(circle at 92% 10%, rgba(var(--brass-rgb), 0.07) 0%, transparent 40%);
    opacity: 0.65;
}
[data-theme="dark"] body::before { opacity: 0.4; }
nav, header, section, footer, main { position: relative; z-index: 1; }

/* Navbar */
.navbar {
    position: sticky; top: 0; width: 100%; z-index: 1000;
    background: rgba(246, 241, 230, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    display: flex; justify-content: space-between; align-items: center;
    padding: 0 5%; height: 68px; gap: 18px;
}
[data-theme="dark"] .navbar { background: rgba(28, 23, 16, 0.92); }
.nav-brand { font-size: 17px; font-weight: 800; color: var(--text-main); display: flex; align-items: center; gap: 10px; letter-spacing: 0.2px; flex-shrink: 0; font-family: var(--font-serif); }
.nav-brand .brand-cn { color: var(--text-main); }
.nav-brand .brand-en { color: var(--text-soft); font-weight: 700; font-size: 11px; letter-spacing: 1.5px; margin-left: 2px; font-family: -apple-system, "Segoe UI", sans-serif; }
.book-mark { position: relative; width: 30px; height: 30px; border-radius: 6px; flex-shrink: 0; display: flex; align-items: center; justify-content: center; font-size: 15px; background: var(--bg-panel); border: 1px solid rgba(var(--brass-rgb), 0.45); box-shadow: inset 2px 0 0 rgba(var(--primary-rgb), 0.55); }
.menu-toggle { display: none; font-size: 24px; cursor: pointer; color: var(--text-main); background: none; border: none; }
.nav-menu-wrapper { display: flex; align-items: center; gap: 20px; flex: 1; justify-content: flex-end; min-width: 0; }
.nav-links { display: flex; gap: 18px; flex-wrap: nowrap; }
.nav-links a { font-weight: 600; font-size: 13.5px; color: var(--text-muted); transition: color 0.2s; white-space: nowrap; }
.nav-links a:hover, .nav-links a.is-current { color: var(--primary); }
.nav-tools { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.search-box { position: relative; }
.search-box input { width: 158px; padding: 7px 12px 7px 30px; border-radius: 20px; border: 1px solid var(--border-color); background: var(--bg-card); color: var(--text-main); font-size: 13px; outline: none; transition: width 0.2s, border-color 0.2s; }
.search-box input:focus { width: 200px; border-color: rgba(var(--primary-rgb), 0.5); }
.search-box .search-icon { position: absolute; left: 10px; top: 50%; transform: translateY(-50%); font-size: 12px; color: var(--text-soft); pointer-events: none; }
.search-results { position: absolute; top: calc(100% + 8px); right: 0; width: 300px; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; box-shadow: 0 14px 34px rgba(40, 25, 10, 0.16); padding: 8px; display: none; max-height: 340px; overflow-y: auto; z-index: 1200; }
.search-results.active { display: block; }
.search-results a { display: block; padding: 9px 11px; border-radius: 8px; font-size: 13.5px; color: var(--text-main); }
.search-results a:hover { background: var(--bg-panel); }
.search-results a small { display: block; color: var(--text-soft); font-size: 11.5px; margin-top: 2px; font-weight: 400; }
.search-empty { padding: 10px 11px; font-size: 13px; color: var(--text-soft); }
.theme-toggle { display: flex; align-items: center; justify-content: center; width: 34px; height: 34px; border-radius: 50%; border: 1px solid var(--border-color); background: var(--bg-card); color: var(--text-main); font-size: 14px; cursor: pointer; flex-shrink: 0; }
.theme-toggle:hover { border-color: rgba(var(--primary-rgb), 0.5); }
.nav-actions .btn { padding: 9px 18px; font-size: 13.5px; }

/* Buttons */
.btn { display: inline-block; padding: 12px 26px; border-radius: 8px; font-weight: 700; text-align: center; transition: all 0.2s; cursor: pointer; border: 1px solid transparent; font-size: 15px; }
.btn-primary { background: var(--primary); color: #fff9f2; box-shadow: 0 8px 20px rgba(var(--primary-rgb), 0.24); }
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-1px); }
[data-theme="dark"] .btn-primary { color: #241014; }
.btn-brass { background: var(--brass); color: #2a2117; box-shadow: 0 8px 20px rgba(var(--brass-rgb), 0.26); }
.btn-brass:hover { filter: brightness(1.06); transform: translateY(-1px); }
.btn-outline { border: 1px solid var(--border-color); color: var(--text-main); background: var(--bg-card); }
.btn-outline:hover { border-color: var(--primary); color: var(--primary); }
.btn-sm { padding: 8px 18px; font-size: 13.5px; }
.btn-block { display: block; width: 100%; }

/* ============ Homepage: book-cover hero ============ */
.cover-hero { text-align: center; padding: 88px 5% 56px; border-bottom: 1px solid var(--border-color); background: radial-gradient(ellipse 900px 460px at 50% -14%, rgba(var(--primary-rgb), 0.08), transparent 70%); }
.cover-edition { display: inline-flex; align-items: center; gap: 8px; flex-wrap: wrap; justify-content: center; background: var(--bg-card); border: 1px solid var(--border-color); color: var(--text-soft); padding: 7px 18px; border-radius: 20px; font-size: 12.5px; font-weight: 600; margin-bottom: 26px; }
.cover-edition .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--good); box-shadow: 0 0 7px 1px rgba(var(--good-rgb), 0.7); flex-shrink: 0; }
.cover-hero h1 { font-family: var(--font-serif); font-size: 42px; line-height: 1.4; margin-bottom: 16px; color: var(--text-main); max-width: 780px; margin-inline: auto; }
.cover-hero h1 em { color: var(--primary); font-style: normal; }
.cover-subtitle { font-size: 16.5px; color: var(--text-muted); max-width: 620px; margin: 0 auto 28px; }
.cover-lede { font-size: 15px; color: var(--text-muted); max-width: 700px; margin: 0 auto 30px; text-align: left; background: var(--bg-card); border: 1px solid var(--border-color); border-left: 3px solid var(--brass); border-radius: 4px; padding: 18px 24px; }
.cover-lede strong { color: var(--primary-dark); }
[data-theme="dark"] .cover-lede strong { color: var(--primary-bright); }
.cover-btns { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* Section head */
.section-head { text-align: center; margin-bottom: 40px; }
.section-head .eyebrow { display: inline-block; font-size: 12px; font-weight: 700; color: var(--primary-dark); background: rgba(var(--primary-rgb), 0.09); padding: 4px 14px; border-radius: 20px; margin-bottom: 14px; letter-spacing: 1px; }
[data-theme="dark"] .section-head .eyebrow { color: var(--primary-bright); }
.section-head h2 { font-family: var(--font-serif); font-size: 27px; margin-bottom: 10px; color: var(--text-main); }
.section-head p { font-size: 15px; color: var(--text-muted); max-width: 640px; margin: 0 auto; }
.section-head.align-left { text-align: left; }
.section-head.align-left p { margin: 0; }

/* ============ Table of contents (homepage) ============ */
.toc-list { max-width: 820px; margin: 0 auto; border-top: 1px solid var(--border-color); }
.toc-item { display: flex; align-items: flex-start; gap: 22px; padding: 26px 6px; border-bottom: 1px solid var(--border-color); transition: background 0.15s; }
.toc-item:hover { background: rgba(var(--brass-rgb), 0.06); }
.toc-num { font-family: var(--font-serif); font-size: 30px; color: var(--brass); font-weight: 700; min-width: 58px; text-align: right; line-height: 1.2; flex-shrink: 0; }
.toc-num small { display: block; font-size: 11px; color: var(--text-soft); font-weight: 600; letter-spacing: 1px; font-family: -apple-system, sans-serif; }
.toc-body { flex: 1; }
.toc-body h3 { font-size: 17px; margin-bottom: 6px; }
.toc-body h3 a { color: var(--text-main); }
.toc-body h3 a:hover { color: var(--primary); }
.toc-body p { font-size: 13.8px; color: var(--text-muted); }
.toc-arrow { font-size: 13px; font-weight: 700; color: var(--primary); align-self: center; flex-shrink: 0; white-space: nowrap; }
[data-theme="dark"] .toc-arrow { color: var(--primary-bright); }

/* ============ Reference-service intro (homepage closing) ============ */
.disclosure-banner { max-width: 900px; margin: 0 auto 22px; background: rgba(var(--brass-rgb), 0.08); border: 1px dashed rgba(var(--brass-rgb), 0.5); border-radius: 10px; padding: 14px 20px; font-size: 13px; color: var(--text-muted); text-align: center; }
.disclosure-banner strong { color: var(--brass); }
.reference-card { max-width: 900px; margin: 0 auto; background: var(--bg-card); border: 1px solid rgba(var(--primary-rgb), 0.28); border-radius: 16px; padding: 32px; box-shadow: 0 20px 44px rgba(40, 25, 10, 0.07); }
[data-theme="dark"] .reference-card { box-shadow: 0 20px 44px rgba(0,0,0,0.35); }
.reference-head { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 10px; margin-bottom: 18px; }
.reference-tag { display: inline-flex; align-items: center; gap: 6px; background: var(--brass); color: #2a2117; font-size: 11px; font-weight: 800; padding: 5px 13px; border-radius: 20px; letter-spacing: 0.5px; }
.reference-title { font-family: var(--font-serif); font-size: 21px; font-weight: 700; color: var(--text-main); }
.reference-grid { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 14px; margin-bottom: 20px; }
.reference-spec { background: var(--bg-panel); border-radius: 10px; padding: 14px; }
.reference-spec .rs-label { font-size: 11.5px; color: var(--text-soft); margin-bottom: 5px; }
.reference-spec .rs-value { font-size: 14px; font-weight: 700; color: var(--text-main); line-height: 1.4; }
.reference-actions { display: flex; gap: 14px; flex-wrap: wrap; align-items: center; }

/* ============ Chapter / book-shell layout ============ */
.book-shell { display: grid; grid-template-columns: 246px 1fr; gap: 46px; max-width: 1180px; margin: 0 auto; padding: 44px 5% 90px; align-items: start; }
.book-sidebar { position: sticky; top: 88px; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 20px; }
.book-sidebar h4 { font-size: 12px; letter-spacing: 1px; color: var(--text-soft); text-transform: uppercase; margin-bottom: 14px; }
.book-sidebar ol { display: flex; flex-direction: column; gap: 2px; }
.book-sidebar li a { display: block; padding: 9px 10px; border-radius: 8px; font-size: 13.5px; color: var(--text-muted); border-left: 3px solid transparent; }
.book-sidebar li a:hover { background: var(--bg-panel); color: var(--text-main); }
.book-sidebar li a.is-current { background: rgba(var(--primary-rgb), 0.09); color: var(--primary-dark); border-left-color: var(--primary); font-weight: 700; }
[data-theme="dark"] .book-sidebar li a.is-current { color: var(--primary-bright); }
.book-sidebar .sidebar-divider { height: 1px; background: var(--border-color); margin: 12px 0; }

.chapter-col { max-width: 760px; }
.breadcrumb { font-size: 13px; color: var(--text-soft); margin-bottom: 20px; }
.breadcrumb a { color: var(--text-muted); }
.breadcrumb a:hover { color: var(--primary); }
.chapter-kicker { display: block; font-size: 12.5px; font-weight: 700; color: var(--brass); letter-spacing: 2px; margin-bottom: 10px; text-transform: uppercase; }
.chapter-col h1 { font-family: var(--font-serif); font-size: 30px; line-height: 1.44; margin-bottom: 14px; color: var(--text-main); }
.chapter-dek { font-size: 15.5px; color: var(--text-muted); margin-bottom: 22px; }
.chapter-meta { font-size: 12.5px; color: var(--text-soft); margin-bottom: 30px; padding-bottom: 20px; border-bottom: 1px solid var(--border-color); display: flex; gap: 16px; flex-wrap: wrap; }
.summary-box { background: var(--bg-card); border: 1px solid var(--border-color); border-left: 3px solid var(--primary); border-radius: 4px; padding: 18px 22px; margin-bottom: 30px; font-size: 15px; color: var(--text-muted); }
.summary-box strong { color: var(--primary-dark); }
[data-theme="dark"] .summary-box strong { color: var(--primary-bright); }

.prose h2 { font-family: var(--font-serif); font-size: 21px; margin: 34px 0 14px; color: var(--text-main); }
.prose h3 { font-size: 16.5px; margin: 24px 0 10px; color: var(--text-main); font-weight: 700; }
.prose p { font-size: 15.3px; color: var(--text-muted); margin-bottom: 16px; }
.prose ul, .prose ol.decimal { padding-left: 22px; margin-bottom: 16px; color: var(--text-muted); }
.prose ul { list-style: disc; }
.prose ol.decimal { list-style: decimal; }
.prose li { margin-bottom: 7px; font-size: 15.3px; }
.prose a { color: var(--primary); text-decoration: underline; }
[data-theme="dark"] .prose a { color: var(--primary-bright); }
.prose table { width: 100%; border-collapse: collapse; margin: 18px 0 26px; font-size: 14px; }
.prose th, .prose td { border: 1px solid var(--border-color); padding: 10px 12px; text-align: left; }
.prose th { background: var(--bg-panel); }

.inline-note { background: var(--bg-card-2); border: 1px solid var(--border-color); border-left: 4px solid var(--brass); border-radius: 8px; padding: 20px 22px; margin: 30px 0; }
.inline-note h4 { font-size: 15.5px; margin-bottom: 8px; color: var(--text-main); }
.inline-note p { font-size: 13.8px; color: var(--text-muted); margin-bottom: 10px; }

.quick-access { display: flex; gap: 24px; align-items: center; flex-wrap: wrap; background: var(--bg-card); border: 1px solid rgba(var(--primary-rgb), 0.28); border-radius: 14px; padding: 24px 26px; margin-bottom: 34px; }
.quick-access .qa-text { flex: 1; min-width: 220px; }
.quick-access .qa-text h3 { font-size: 16.5px; margin-bottom: 6px; font-family: var(--font-serif); }
.quick-access .qa-text p { font-size: 13.3px; color: var(--text-muted); }
.promo-pill { display: inline-flex; align-items: center; gap: 8px; background: rgba(var(--brass-rgb), 0.1); border: 1px dashed rgba(var(--brass-rgb), 0.55); border-radius: 8px; padding: 8px 14px; font-size: 13px; color: var(--brass); margin-top: 10px; }
.promo-pill code { background: transparent; color: var(--brass); font-weight: 800; letter-spacing: 1px; padding: 0; }

.spec-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-bottom: 10px; }
.spec-card { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 18px 16px; }
.spec-card .spec-label { font-size: 11.5px; color: var(--text-soft); margin-bottom: 8px; }
.spec-card .spec-value { font-size: 14.5px; font-weight: 700; color: var(--text-main); line-height: 1.4; }
.spec-note { font-size: 12px; color: var(--text-soft); margin: 12px 0 34px; }

.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; margin: 24px 0 10px; }
.pro-list, .caution-list { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 20px 22px; }
.pro-list h4, .caution-list h4 { font-size: 14.5px; margin-bottom: 12px; }
.pro-list h4 { color: var(--good); }
.caution-list h4 { color: var(--danger); }
.pro-list li, .caution-list li { font-size: 13.8px; color: var(--text-muted); margin-bottom: 9px; padding-left: 18px; position: relative; list-style: none; }
.pro-list li::before { content: "✓"; position: absolute; left: 0; color: var(--good); font-weight: 800; }
.caution-list li::before { content: "!"; position: absolute; left: 2px; color: var(--danger); font-weight: 800; }

.shop-wrap { max-width: 100%; margin: 0 auto; overflow-x: auto; }
.shop-table { width: 100%; border-collapse: separate; border-spacing: 0; min-width: 700px; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 14px; overflow: hidden; }
.shop-table th, .shop-table td { padding: 15px 16px; text-align: left; font-size: 13.6px; border-bottom: 1px solid var(--border-soft); vertical-align: top; }
.shop-table thead th { background: var(--bg-panel); color: var(--text-soft); font-size: 11.5px; text-transform: uppercase; letter-spacing: 0.5px; }
.shop-table tbody tr:last-child td { border-bottom: none; }
.shop-table tbody tr.is-reco { background: rgba(var(--primary-rgb), 0.06); }
.reco-chip { background: var(--primary); color: #fff9f2; font-size: 10.5px; font-weight: 800; padding: 2px 9px; border-radius: 10px; margin-left: 6px; }
[data-theme="dark"] .reco-chip { color: #241014; }
.compare-fineprint { font-size: 12.3px; color: var(--text-soft); margin-top: 14px; }

.related-links { margin-top: 44px; padding-top: 24px; border-top: 1px solid var(--border-color); }
.related-links h4 { font-size: 14px; margin-bottom: 12px; color: var(--text-soft); }
.related-links li { list-style: none; margin-bottom: 8px; }
.related-links a { color: var(--primary); font-weight: 600; font-size: 14.3px; }
[data-theme="dark"] .related-links a { color: var(--primary-bright); }

/* Chapter bottom sequential nav */
.chapter-nav-footer { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 48px; padding-top: 30px; border-top: 1px solid var(--border-color); }
.chapter-nav-footer .cn-card { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 18px 20px; transition: border-color 0.2s, transform 0.2s; }
.chapter-nav-footer .cn-card:hover { border-color: rgba(var(--primary-rgb), 0.4); transform: translateY(-2px); }
.chapter-nav-footer .cn-card.next { text-align: right; }
.chapter-nav-footer .cn-dir { display: block; font-size: 11.5px; color: var(--text-soft); margin-bottom: 6px; letter-spacing: 0.5px; }
.chapter-nav-footer .cn-title { font-size: 15px; font-weight: 700; color: var(--text-main); font-family: var(--font-serif); }

/* Client download grid (used within chapter-4, not homepage-dominant) */
.client-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 14px; margin: 24px 0 10px; }
.client-card { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 20px 14px; text-align: center; transition: transform 0.2s, border-color 0.2s; }
.client-card:hover { transform: translateY(-3px); border-color: rgba(var(--primary-rgb), 0.32); }
.client-card .client-icon { font-size: 25px; margin-bottom: 10px; }
.client-card h4 { font-size: 14.5px; margin-bottom: 6px; }
.client-card .client-os { font-size: 11px; color: var(--text-soft); background: var(--bg-panel); display: inline-block; padding: 2px 9px; border-radius: 6px; margin-bottom: 10px; }
.client-card p { font-size: 12.3px; color: var(--text-muted); margin-bottom: 14px; min-height: 50px; }
.mirror-note { background: var(--bg-card); border: 1px solid var(--border-color); border-left: 4px solid var(--brass); border-radius: 10px; padding: 18px 22px; font-size: 13.5px; color: var(--text-muted); margin: 24px 0; }
.mirror-note strong { color: var(--brass); }

/* Troubleshooting numbered problem list (chapter-5) */
.problem-list { display: flex; flex-direction: column; gap: 4px; }
.problem-item { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 20px 22px; margin-bottom: 14px; }
.problem-item .p-num { display: inline-block; font-family: var(--font-serif); font-size: 13px; font-weight: 700; color: var(--primary); background: rgba(var(--primary-rgb), 0.08); padding: 2px 11px; border-radius: 20px; margin-bottom: 10px; }
[data-theme="dark"] .problem-item .p-num { color: var(--primary-bright); }
.problem-item h3 { font-size: 15.5px; margin-bottom: 8px; color: var(--text-main); }
.problem-item p { font-size: 14px; color: var(--text-muted); margin-bottom: 6px; }

/* Glossary (appendix) */
.glossary-list { display: flex; flex-direction: column; }
.glossary-item { padding: 20px 0; border-bottom: 1px solid var(--border-color); }
.glossary-item dt { font-family: var(--font-serif); font-size: 16.5px; font-weight: 700; color: var(--text-main); margin-bottom: 8px; }
.glossary-item dt .term-en { font-size: 12px; color: var(--text-soft); font-weight: 500; margin-left: 8px; font-family: -apple-system, sans-serif; }
.glossary-item dd { font-size: 14.3px; color: var(--text-muted); }

/* FAQ */
.faq-list { max-width: 100%; }
.faq-list details { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 10px; padding: 16px 20px; margin-bottom: 10px; }
.faq-list details[open] { border-color: rgba(var(--primary-rgb), 0.35); }
.faq-list summary { font-weight: 700; cursor: pointer; font-size: 15px; list-style: none; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::before { content: "▸"; color: var(--primary); margin-right: 10px; display: inline-block; transition: transform 0.2s; }
[data-theme="dark"] .faq-list summary::before { color: var(--primary-bright); }
.faq-list details[open] summary::before { transform: rotate(90deg); }
.faq-list p { margin-top: 10px; font-size: 14px; color: var(--text-muted); }

/* Bottom CTA */
.bottom-cta { text-align: center; background: linear-gradient(120deg, rgba(var(--primary-rgb),0.1), rgba(var(--brass-rgb),0.08)); border: 1px solid rgba(var(--primary-rgb),0.22); border-radius: 20px; max-width: 1140px; margin: 0 auto; padding: 52px 5%; }
.bottom-cta h2 { font-family: var(--font-serif); font-size: 24px; margin-bottom: 12px; color: var(--text-main); }
.bottom-cta p { color: var(--text-muted); margin-bottom: 22px; font-size: 15px; }

/* Subpage (about/terms/privacy/sitemap) */
.subpage-header { padding: 90px 5% 42px; text-align: center; border-bottom: 1px solid var(--border-color); background: radial-gradient(ellipse 700px 380px at 50% -20%, rgba(var(--primary-rgb), 0.08), transparent 70%); }
.subpage-header h1 { font-family: var(--font-serif); font-size: 28px; margin-bottom: 10px; color: var(--text-main); }
.subpage-header p { color: var(--text-muted); font-size: 15px; }
.subpage-content { padding: 52px 5%; max-width: 780px; margin: 0 auto; color: var(--text-muted); font-size: 15.3px; }
.subpage-content h2 { font-family: var(--font-serif); color: var(--text-main); margin: 28px 0 14px; font-size: 19.5px; }
.subpage-content p { margin-bottom: 15px; }
.subpage-content ul { padding-left: 20px; margin-bottom: 15px; list-style: disc; }
.subpage-content li { margin-bottom: 7px; }

/* Footer */
footer { border-top: 1px solid var(--border-color); padding: 50px 5% 32px; background: var(--bg-page-alt); color: var(--text-muted); text-align: center; }
.footer-logo { font-family: var(--font-serif); font-size: 18px; font-weight: 800; color: var(--text-main); margin-bottom: 22px; display: flex; align-items: center; justify-content: center; gap: 9px; }
.footer-links { display: flex; justify-content: center; gap: 26px; margin-bottom: 24px; flex-wrap: wrap; }
.footer-links a { color: var(--text-muted); transition: color 0.2s; font-size: 14px; }
.footer-links a:hover { color: var(--primary); }
.footer-friends { margin-bottom: 20px; font-size: 13.3px; color: var(--text-soft); }
.footer-friends a { color: var(--text-soft); transition: color 0.2s; margin: 0 8px; }
.footer-friends a:hover { color: var(--primary); }
.footer-disclosure { font-size: 12px; color: var(--text-soft); max-width: 700px; margin: 0 auto 18px; line-height: 1.6; }
.footer-copy { color: var(--text-soft); font-size: 12.3px; }

/* Mobile */
@media (max-width: 1020px) {
    .book-shell { grid-template-columns: 1fr; }
    .book-sidebar { position: static; }
    .spec-grid { grid-template-columns: repeat(2, 1fr); }
    .client-grid { grid-template-columns: repeat(3, 1fr); }
    .reference-grid { grid-template-columns: repeat(3, 1fr); }
}
@media (max-width: 768px) {
    .nav-menu-wrapper { display: none; flex-direction: column; align-items: stretch; position: absolute; top: 68px; left: 0; width: 100%; background: var(--bg-page); padding: 22px 20px; border-bottom: 1px solid var(--border-color); gap: 16px; }
    .nav-menu-wrapper.active { display: flex; }
    .menu-toggle { display: block; }
    .nav-links { flex-direction: column; gap: 14px; text-align: center; width: 100%; }
    .nav-tools { justify-content: center; }
    .search-box input, .search-box input:focus { width: 100%; }
    .cover-hero h1 { font-size: 27px; }
    .cover-lede { font-size: 14px; }
    section { padding: 44px 5%; }
    .chapter-col h1 { font-size: 23px; }
    .footer-links { gap: 14px; flex-direction: column; }
    .spec-grid { grid-template-columns: 1fr 1fr; }
    .two-col { grid-template-columns: 1fr; }
    .reference-grid { grid-template-columns: 1fr 1fr; }
    .client-grid { grid-template-columns: repeat(2, 1fr); }
    .chapter-nav-footer { grid-template-columns: 1fr; }
    .chapter-nav-footer .cn-card.next { text-align: left; }
    .toc-item { flex-wrap: wrap; }
    .toc-arrow { margin-left: 78px; }
}
@media (max-width: 420px) {
    .quick-access, .spec-grid, .client-grid, .reference-grid { grid-template-columns: 1fr; }
}