/* ============================================================
   梯子工具实验室 (vpn-tools-lab) — original visual identity
   Concept: "工具研究实验室 / spec-sheet lab notebook" —
   an information-dense measurement-and-comparison look, built
   around monospace data tags, hexagon lab-node marks and a
   faint dot-grid "lab bench" texture. Light background for
   long-form Chinese reading comfort.
   Palette: indigo primary (research/authority) + acid-lime
   accent (active/positive signal) + amber reserved only for
   the dominant 无忧链接 recommendation.
   Deliberately distinct from sibling sites in this repo:
   itz.mom (cream+green+orange nav-hub), itz.lat (dark navy+
   cyan), ifq.lol (light purple+coral "VPN LAB" flask hub),
   ifq.homes (warm paper+burgundy+brass), efq.homes (white+
   navy+teal single-dossier report).
   ============================================================ */

:root {
    --bg-page: #f5f6fb;
    --bg-page-alt: #eef0f9;
    --bg-card: #ffffff;
    --bg-card-2: #f8f9fd;
    --bg-panel: #eef0f9;
    --bg-dark: #14163a;
    --bg-dark-2: #1c1f4d;
    --border-color: #e0e2f0;
    --border-soft: #eaecf6;
    --primary: #3f34a8;
    --primary-dark: #2a2273;
    --primary-rgb: 63, 52, 168;
    --primary-bright: #5b4de0;
    --accent: #5f9e00;
    --accent-dark: #4a7d00;
    --accent-rgb: 95, 158, 0;
    --gold: #b8790a;
    --gold-dark: #935f07;
    --gold-rgb: 184, 121, 10;
    --gold-bg: #fff6e6;
    --text-main: #171933;
    --text-muted: #565a7c;
    --text-soft: #8b8fb0;
    --text-invert: #f3f4fc;
    --danger: #c5312a;
    --danger-rgb: 197, 49, 42;
    --good: #4a7d00;
    --font-mono: "SFMono-Regular", Consolas, "Roboto Mono", monospace;
    color-scheme: light;
}

* { 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: 1.72;
}
a { text-decoration: none; color: inherit; }
ul, ol { list-style: none; }
img { max-width: 100%; display: block; }
code { background: rgba(var(--primary-rgb), 0.08); color: var(--primary-dark); padding: 2px 6px; border-radius: 4px; font-size: 0.92em; font-family: var(--font-mono); }
.container { max-width: 1160px; margin: 0 auto; padding: 0 5%; }
section { padding: 56px 5%; position: relative; }
h1, h2, h3, h4 { line-height: 1.35; font-weight: 700; }

/* faint dot-grid "lab bench" texture */
body::before {
    content: "";
    position: fixed;
    inset: 0;
    z-index: -1;
    pointer-events: none;
    background-image: radial-gradient(rgba(var(--primary-rgb), 0.09) 1px, transparent 1px);
    background-size: 22px 22px;
    -webkit-mask-image: radial-gradient(ellipse 1200px 700px at 50% 0%, black 0%, transparent 70%);
    mask-image: radial-gradient(ellipse 1200px 700px at 50% 0%, black 0%, transparent 70%);
}

/* ---------------- nav ---------------- */
.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 5%;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 50;
}
.nav-brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 18px; white-space: nowrap; }
.lab-mark {
    width: 30px; height: 30px; flex-shrink: 0;
    background: linear-gradient(145deg, var(--primary-bright), var(--primary-dark));
    clip-path: polygon(50% 0%, 100% 25%, 100% 75%, 50% 100%, 0% 75%, 0% 25%);
    position: relative;
}
.lab-mark::after {
    content: "";
    position: absolute; inset: 8px;
    background: var(--accent);
    clip-path: polygon(50% 0%, 100% 25%, 100% 75%, 50% 100%, 0% 75%, 0% 25%);
}
.brand-cn { color: var(--text-main); }
.brand-en { display: block; font-size: 10.5px; font-weight: 600; letter-spacing: 1.5px; color: var(--text-soft); text-transform: uppercase; }
.menu-toggle { display: none; background: none; border: none; font-size: 22px; cursor: pointer; color: var(--text-main); }
.nav-menu-wrapper { display: flex; align-items: center; gap: 26px; }
.nav-links { display: flex; gap: 22px; font-size: 14.5px; font-weight: 600; color: var(--text-muted); }
.nav-links a:hover, .nav-links a.is-current { color: var(--primary); }
.nav-actions .btn { padding: 9px 18px; font-size: 14px; }

.btn {
    display: inline-block;
    padding: 12px 26px;
    border-radius: 8px;
    font-weight: 700;
    font-size: 15px;
    cursor: pointer;
    border: 2px solid transparent;
    transition: transform 0.15s ease, box-shadow 0.15s ease;
    text-align: center;
}
.btn:hover { transform: translateY(-1px); }
.btn-primary { background: var(--primary); color: #fff; box-shadow: 0 6px 16px rgba(var(--primary-rgb), 0.28); }
.btn-primary:hover { background: var(--primary-dark); }
.btn-gold { background: linear-gradient(135deg, #d99a1c, var(--gold)); color: #2a1b00; box-shadow: 0 8px 20px rgba(var(--gold-rgb), 0.35); }
.btn-gold:hover { background: var(--gold-dark); color: #fff; }
.btn-outline { background: transparent; border-color: var(--border-color); color: var(--text-main); }
.btn-outline:hover { border-color: var(--primary); color: var(--primary); }
.btn-sm { padding: 8px 16px; font-size: 13.5px; }
.btn-block { display: block; width: 100%; }

/* ---------------- hero ---------------- */
.hero {
    text-align: center;
    padding: 62px 5% 40px;
    max-width: 880px;
    margin: 0 auto;
}
.eyebrow-pill {
    display: inline-flex; align-items: center; gap: 6px;
    background: var(--bg-panel); color: var(--primary);
    padding: 6px 14px; border-radius: 999px;
    font-size: 12.5px; font-weight: 700; margin-bottom: 18px;
    font-family: var(--font-mono);
}
.hero h1 { font-size: 34px; margin-bottom: 16px; color: var(--text-main); }
.hero p.lede { font-size: 16.5px; color: var(--text-muted); max-width: 680px; margin: 0 auto 22px; }
.hero-stats { display: flex; flex-wrap: wrap; justify-content: center; gap: 22px; margin-top: 26px; font-size: 13.5px; color: var(--text-soft); }
.hero-stats span { display: flex; align-items: center; gap: 6px; }

/* ---------------- breadcrumb ---------------- */
.breadcrumb { font-size: 13px; color: var(--text-soft); margin-bottom: 18px; }
.breadcrumb a { color: var(--text-muted); }
.breadcrumb a:hover { color: var(--primary); }

/* ---------------- section head ---------------- */
.section-head { text-align: center; max-width: 720px; margin: 0 auto 34px; }
.eyebrow { display: inline-block; font-family: var(--font-mono); font-size: 12px; font-weight: 700; letter-spacing: 1.5px; text-transform: uppercase; color: var(--accent-dark); background: rgba(var(--accent-rgb), 0.1); padding: 4px 10px; border-radius: 5px; margin-bottom: 10px; }
.section-head h2 { font-size: 25px; margin-bottom: 8px; }
.section-head p { color: var(--text-muted); font-size: 15px; }

/* ---------------- ranking tier grid (index) ---------------- */
.tier-stack { display: flex; flex-direction: column; gap: 18px; max-width: 920px; margin: 0 auto; }

.rank-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 14px;
    padding: 22px 24px;
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 18px;
    align-items: center;
}
.rank-num {
    width: 34px; height: 34px; border-radius: 8px;
    background: var(--bg-panel); color: var(--text-muted);
    display: flex; align-items: center; justify-content: center;
    font-weight: 800; font-family: var(--font-mono); font-size: 15px;
}
.rank-body h3 { font-size: 17px; margin-bottom: 4px; }
.rank-body .rank-tag { font-size: 12px; color: var(--text-soft); font-weight: 600; margin-left: 8px; }
.rank-body p { font-size: 13.5px; color: var(--text-muted); }
.rank-actions { display: flex; flex-direction: column; gap: 8px; align-items: flex-end; }
.rank-actions .price { font-family: var(--font-mono); font-size: 13px; color: var(--text-soft); white-space: nowrap; }

/* dominant #1 card — clearly heavier weight */
.rank-card.is-dominant {
    grid-template-columns: 1fr;
    background: linear-gradient(155deg, #fffaf0, #fff);
    border: 2px solid var(--gold);
    border-radius: 18px;
    padding: 32px 34px;
    box-shadow: 0 18px 40px rgba(var(--gold-rgb), 0.16);
    position: relative;
    overflow: hidden;
}
.rank-card.is-dominant::before {
    content: "本站首推";
    position: absolute; top: 18px; right: -38px;
    background: var(--gold); color: #2a1b00;
    font-size: 12px; font-weight: 800;
    padding: 5px 44px; transform: rotate(38deg);
    font-family: var(--font-mono);
}
.dominant-head { display: flex; align-items: center; gap: 14px; margin-bottom: 14px; }
.dominant-badge { width: 52px; height: 52px; border-radius: 12px; background: linear-gradient(145deg, var(--gold), #935f07); display: flex; align-items: center; justify-content: center; color: #fff; font-weight: 900; font-size: 22px; flex-shrink: 0; }
.dominant-head h3 { font-size: 24px; }
.dominant-head .rank-tag { font-size: 13px; font-weight: 700; color: var(--gold-dark); }
.dominant-lede { font-size: 15.5px; color: var(--text-muted); margin-bottom: 18px; max-width: 780px; }
.dominant-specs { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-bottom: 22px; }
.dominant-specs .d-spec { background: rgba(255,255,255,0.6); border: 1px solid rgba(var(--gold-rgb), 0.25); border-radius: 10px; padding: 12px 14px; }
.dominant-specs .d-label { font-size: 11.5px; color: var(--text-soft); font-family: var(--font-mono); text-transform: uppercase; margin-bottom: 4px; }
.dominant-specs .d-value { font-size: 14px; font-weight: 700; color: var(--text-main); }
.dominant-cta { display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }
.dominant-cta .coupon { font-family: var(--font-mono); font-size: 13px; color: var(--text-muted); }

/* ---------------- spec grid (generic) ---------------- */
.spec-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; margin: 20px 0; }
.spec-card { background: var(--bg-card-2); border: 1px solid var(--border-soft); border-radius: 10px; padding: 14px 16px; }
.spec-label { font-family: var(--font-mono); font-size: 11.5px; color: var(--text-soft); text-transform: uppercase; letter-spacing: 0.5px; margin-bottom: 5px; }
.spec-value { font-size: 14.5px; font-weight: 600; color: var(--text-main); }
.spec-note { font-size: 12.5px; color: var(--text-soft); max-width: 900px; margin: 4px auto; text-align: center; }

/* ---------------- product detail page ---------------- */
.article-wrap { max-width: 940px; margin: 0 auto; padding: 40px 5% 70px; }
.article-wrap h1 { font-size: 28px; margin-bottom: 10px; }
.article-meta { display: flex; flex-wrap: wrap; gap: 14px; font-size: 12.5px; color: var(--text-soft); margin-bottom: 26px; font-family: var(--font-mono); }
.detail-block { margin-bottom: 30px; }
.detail-block h2 { font-size: 21px; margin-bottom: 12px; padding-bottom: 8px; border-bottom: 2px solid var(--bg-panel); }
.detail-block p { color: var(--text-muted); margin-bottom: 12px; font-size: 15px; }
.quick-access { display: flex; align-items: center; justify-content: space-between; gap: 20px; background: var(--bg-panel); border-radius: 14px; padding: 22px 26px; margin-bottom: 30px; flex-wrap: wrap; }
.quick-access .qa-text { flex: 1 1 320px; min-width: 220px; }
.quick-access h3 { font-size: 16px; margin-bottom: 6px; }
.quick-access p { font-size: 13.5px; color: var(--text-muted); margin-bottom: 8px; }
.promo-pill { display: inline-block; font-size: 12.5px; background: #fff; border: 1px dashed var(--gold); color: var(--gold-dark); padding: 5px 12px; border-radius: 999px; }
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.pro-list, .caution-list { background: var(--bg-card-2); border: 1px solid var(--border-soft); border-radius: 10px; padding: 16px 18px; }
.pro-list h4, .caution-list h4 { font-size: 14.5px; margin-bottom: 10px; }
.pro-list ul li, .caution-list ul li { font-size: 13.5px; color: var(--text-muted); padding-left: 16px; position: relative; margin-bottom: 8px; }
.pro-list ul li::before { content: "✓"; position: absolute; left: 0; color: var(--accent-dark); font-weight: 700; }
.caution-list ul li::before { content: "!"; position: absolute; left: 2px; color: var(--danger); font-weight: 700; }
.related-links { background: var(--bg-panel); border-radius: 12px; padding: 18px 22px; margin-top: 30px; }
.related-links h4 { font-size: 14px; margin-bottom: 10px; }
.related-links ul li { font-size: 13.5px; margin-bottom: 6px; }
.related-links a { color: var(--primary); font-weight: 600; }
.related-links a:hover { text-decoration: underline; }

/* ---------------- tables ---------------- */
.table-wrap { overflow-x: auto; margin: 20px 0; border-radius: 12px; border: 1px solid var(--border-color); }
table.data-table { width: 100%; border-collapse: collapse; font-size: 14px; background: var(--bg-card); min-width: 640px; }
table.data-table th, table.data-table td { padding: 12px 14px; text-align: left; border-bottom: 1px solid var(--border-soft); vertical-align: top; }
table.data-table th { background: var(--bg-panel); font-family: var(--font-mono); font-size: 12.5px; text-transform: uppercase; color: var(--text-muted); white-space: nowrap; }
table.data-table tr.is-reco { background: rgba(var(--gold-rgb), 0.06); }
table.data-table tr.is-reco td:first-child { border-left: 3px solid var(--gold); }
.reco-chip { display: inline-block; background: var(--gold); color: #2a1b00; font-size: 11px; font-weight: 800; padding: 2px 8px; border-radius: 999px; margin-left: 6px; }
.fineprint { font-size: 12.5px; color: var(--text-soft); max-width: 940px; margin: 12px auto 0; text-align: center; }

/* ---------------- compare page column highlight ---------------- */
table.compare-table th.col-wuyou, table.compare-table td.col-wuyou { background: rgba(var(--gold-rgb), 0.07); }

/* ---------------- FAQ ---------------- */
.faq-list { max-width: 860px; margin: 0 auto; display: flex; flex-direction: column; gap: 10px; }
.faq-list details { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 10px; padding: 16px 20px; }
.faq-list summary { font-weight: 700; font-size: 15px; cursor: pointer; list-style: none; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::before { content: "Q. "; color: var(--primary); font-family: var(--font-mono); }
.faq-list p { margin-top: 10px; font-size: 14px; color: var(--text-muted); }

/* ---------------- guide hub teaser (index) ---------------- */
.teaser-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 18px; max-width: 1000px; margin: 0 auto; }
.teaser-card { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 22px; }
.teaser-icon { font-size: 26px; margin-bottom: 10px; }
.teaser-card h3 { font-size: 16.5px; margin-bottom: 8px; }
.teaser-card p { font-size: 13.5px; color: var(--text-muted); margin-bottom: 14px; }

/* ---------------- CTA banner ---------------- */
.bottom-cta { text-align: center; background: linear-gradient(135deg, var(--bg-dark), var(--bg-dark-2)); color: var(--text-invert); border-radius: 20px; margin: 0 5%; padding: 48px 5%; }
.bottom-cta h2 { font-size: 24px; margin-bottom: 10px; color: #fff; }
.bottom-cta p { color: #c7c9ea; margin-bottom: 22px; font-size: 15px; }

/* ---------------- disclosure ---------------- */
.disclosure-banner { max-width: 900px; margin: 0 auto 24px; background: var(--bg-panel); border: 1px solid var(--border-color); border-radius: 10px; padding: 14px 18px; font-size: 13px; color: var(--text-muted); }

/* ---------------- generic content page (about/terms/privacy) ---------------- */
.static-page { max-width: 820px; margin: 0 auto; padding: 48px 5% 70px; }
.static-page h1 { font-size: 27px; margin-bottom: 18px; }
.static-page h2 { font-size: 19px; margin: 26px 0 10px; }
.static-page p, .static-page li { color: var(--text-muted); font-size: 14.5px; margin-bottom: 10px; }
.static-page ul { padding-left: 6px; }
.static-page li { padding-left: 16px; position: relative; }
.static-page li::before { content: "–"; position: absolute; left: 0; color: var(--text-soft); }

/* ---------------- sitemap page ---------------- */
.sitemap-cols { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 26px; max-width: 940px; margin: 0 auto; }
.sitemap-cols h3 { font-size: 15px; margin-bottom: 10px; color: var(--primary); }
.sitemap-cols li { margin-bottom: 8px; font-size: 14px; }
.sitemap-cols a:hover { text-decoration: underline; }

/* ---------------- footer ---------------- */
footer { background: var(--bg-dark); color: #b7b9dd; padding: 48px 5% 26px; margin-top: 60px; }
.footer-logo { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 17px; color: #fff; max-width: 1160px; margin: 0 auto 18px; }
.footer-links { display: flex; flex-wrap: wrap; gap: 18px; max-width: 1160px; margin: 0 auto 16px; font-size: 13.5px; }
.footer-links a:hover { color: #fff; }
.footer-friends { max-width: 1160px; margin: 0 auto 16px; font-size: 13px; display: flex; flex-wrap: wrap; gap: 14px; align-items: center; border-top: 1px solid rgba(255,255,255,0.1); padding-top: 16px; }
.footer-friends a { color: #9497c9; }
.footer-friends a:hover { color: #fff; }
.footer-disclosure { max-width: 1160px; margin: 0 auto 14px; font-size: 12px; color: #7d80ab; line-height: 1.6; }
.footer-copy { max-width: 1160px; margin: 0 auto; font-size: 12px; color: #6b6e99; }

/* ---------------- responsive ---------------- */
@media (max-width: 900px) {
    .two-col { grid-template-columns: 1fr; }
    .dominant-specs { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 760px) {
    .menu-toggle { display: block; }
    .nav-menu-wrapper {
        display: none;
        position: absolute; top: 100%; left: 0; right: 0;
        background: #fff; border-bottom: 1px solid var(--border-color);
        flex-direction: column; align-items: stretch; padding: 16px 6%;
        gap: 16px;
    }
    .nav-menu-wrapper.active { display: flex; }
    .nav-links { flex-direction: column; gap: 14px; }
    .rank-card { grid-template-columns: 1fr; text-align: left; }
    .rank-actions { align-items: flex-start; flex-direction: row; justify-content: space-between; width: 100%; }
    .hero h1 { font-size: 26px; }
    .dominant-specs { grid-template-columns: 1fr 1fr; }
    .dominant-head h3 { font-size: 20px; }
}