:root {
    --navy: #0f172a;
    --navy-soft: #1e293b;
    --teal: #0d9488;
    --teal-dark: #0f766e;
    --teal-light: #14b8a6;
    --teal-pale: #f0fdfa;
    --ink: #334155;
    --muted: #64748b;
    --line: #e2e8f0;
    --surface: #ffffff;
    --canvas: #f8fafc;
    --warning: #fffbeb;
    --radius: 10px;
    --radius-lg: 18px;
    --width: 1120px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
    background: var(--canvas);
    color: var(--ink);
    font-family: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
    line-height: 1.8;
}
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
.container { width: min(var(--width), calc(100% - 40px)); margin: 0 auto; }

.site-header {
    background: rgba(15, 23, 42, .97);
    border-bottom: 1px solid rgba(255,255,255,.1);
    height: 70px;
    position: sticky;
    top: 0;
    z-index: 20;
}
.nav { align-items: center; display: flex; height: 100%; justify-content: space-between; }
.brand { align-items: center; color: #fff; display: flex; font-size: 1.25rem; font-weight: 700; gap: 10px; }
.brand-mark { color: var(--teal-light); font-size: 1.35rem; }
.nav-links { display: flex; gap: 26px; }
.nav-links a { color: #94a3b8; font-size: .94rem; }
.nav-links a:hover, .nav-links a.active { color: #5eead4; }

.breadcrumb { background: #e2e8f0; color: var(--muted); font-size: .86rem; padding: 11px 0; }
.breadcrumb span { margin: 0 7px; }
.breadcrumb a:hover { color: var(--teal); }

.topic-nav { background: #fff; border-bottom: 1px solid var(--line); position: sticky; top: 70px; z-index: 15; }
.topic-nav-inner { display: flex; gap: 6px; overflow-x: auto; padding: 10px 0; scrollbar-width: none; }
.topic-nav-inner::-webkit-scrollbar { display: none; }
.topic-nav a { border-radius: 7px; color: #475569; flex: 0 0 auto; font-size: .88rem; font-weight: 600; padding: 8px 14px; }
.topic-nav a:hover { background: var(--teal-pale); color: var(--teal-dark); }
.topic-nav a.active { background: var(--teal); color: #fff; }

.hero {
    background: radial-gradient(circle at 82% 20%, rgba(20,184,166,.18), transparent 32%), linear-gradient(135deg, #0f172a, #134e4a);
    color: #fff;
    padding: 78px 0 72px;
}
.hero-inner { max-width: 890px; }
.eyebrow { color: #5eead4; font-size: .82rem; font-weight: 700; letter-spacing: 1.4px; margin-bottom: 14px; text-transform: uppercase; }
.hero h1 { font-size: clamp(2rem, 4vw, 3rem); line-height: 1.32; margin-bottom: 20px; }
.hero .lead { color: #cbd5e1; font-size: 1.08rem; max-width: 820px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 30px; }
.btn { border-radius: 8px; display: inline-block; font-weight: 700; padding: 12px 26px; text-align: center; }
.btn-primary { background: var(--teal); border: 2px solid var(--teal); color: #fff; }
.btn-primary:hover { background: var(--teal-dark); border-color: var(--teal-dark); }
.btn-outline { border: 2px solid rgba(255,255,255,.35); color: #fff; }
.btn-outline:hover { border-color: #5eead4; color: #5eead4; }
.hero-points { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 26px; }
.hero-points span { background: rgba(255,255,255,.08); border: 1px solid rgba(94,234,212,.28); border-radius: 999px; color: #99f6e4; font-size: .82rem; padding: 5px 13px; }

.section { padding: 70px 0; }
.section-alt { background: #f1f5f9; }
.section-head { margin-bottom: 34px; max-width: 760px; }
.section-head.center { margin-left: auto; margin-right: auto; text-align: center; }
.section-head h2 { color: var(--navy); font-size: clamp(1.55rem, 3vw, 2.05rem); line-height: 1.4; margin-bottom: 10px; }
.section-head p { color: var(--muted); }

.answer-box { background: var(--teal-pale); border-left: 5px solid var(--teal); border-radius: var(--radius); color: #115e59; padding: 28px 32px; }
.answer-box h2 { color: #134e4a; font-size: 1.35rem; margin-bottom: 12px; }
.answer-box p + p { margin-top: 10px; }
.answer-box strong { color: var(--teal-dark); }

.grid { display: grid; gap: 20px; }
.grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; }
.card h3 { color: var(--navy); font-size: 1.08rem; margin-bottom: 9px; }
.card p { color: var(--muted); font-size: .92rem; }
.card ul { margin-top: 14px; }
.card li { color: #475569; font-size: .9rem; margin: 8px 0; padding-left: 20px; position: relative; }
.card li::before { color: var(--teal); content: "✓"; font-weight: 700; left: 0; position: absolute; }
.number-card { border-top: 3px solid var(--teal); }
.number { color: var(--teal); font-size: .78rem; font-weight: 800; letter-spacing: 1px; margin-bottom: 8px; }

.table-wrap { overflow-x: auto; }
.data-table { background: #fff; border-collapse: collapse; min-width: 720px; width: 100%; }
.data-table th { background: var(--navy); color: #fff; font-size: .9rem; padding: 14px 16px; text-align: left; }
.data-table td { border-bottom: 1px solid var(--line); color: #475569; font-size: .9rem; padding: 15px 16px; vertical-align: top; }
.data-table tr:nth-child(even) td { background: #f8fafc; }
.data-table strong { color: var(--navy); }

.checklist { background: #fff; border: 1px solid var(--line); border-radius: var(--radius-lg); padding: 30px; }
.checklist h3 { color: var(--navy); margin-bottom: 18px; }
.checklist-grid { display: grid; gap: 12px 28px; grid-template-columns: repeat(2, minmax(0, 1fr)); }
.check-item { border-bottom: 1px dashed #cbd5e1; color: #475569; font-size: .92rem; padding: 8px 0 8px 24px; position: relative; }
.check-item::before { color: var(--teal); content: "□"; font-weight: 700; left: 0; position: absolute; }

.notice { background: var(--warning); border: 1px solid #fde68a; border-radius: var(--radius); color: #92400e; margin-top: 24px; padding: 18px 22px; }
.source-note { border-left: 3px solid #94a3b8; color: var(--muted); font-size: .86rem; margin-top: 22px; padding-left: 15px; }
.source-note a { color: var(--teal-dark); text-decoration: underline; }

.faq { display: grid; gap: 12px; margin: 0 auto; max-width: 900px; }
.faq details { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 0 22px; }
.faq summary { color: var(--navy); cursor: pointer; font-weight: 650; list-style: none; padding: 18px 0; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { color: var(--teal); content: "+"; float: right; font-size: 1.3rem; }
.faq details[open] summary::after { content: "−"; }
.faq .answer { color: #475569; font-size: .92rem; padding: 0 0 20px; }

.lead-section { background: var(--navy); color: #fff; padding: 70px 0; }
.lead-grid { align-items: start; display: grid; gap: 48px; grid-template-columns: .85fr 1.15fr; }
.lead-copy h2 { font-size: 1.9rem; line-height: 1.4; margin-bottom: 14px; }
.lead-copy p { color: #94a3b8; margin-bottom: 18px; }
.lead-copy li { color: #cbd5e1; font-size: .92rem; margin: 9px 0; padding-left: 20px; position: relative; }
.lead-copy li::before { color: #5eead4; content: "✓"; left: 0; position: absolute; }
.lead-contact { color: #94a3b8; font-size: .9rem; margin-top: 22px; }
.lead-contact a { color: #5eead4; }

.lead-form { background: #fff; border-radius: var(--radius-lg); color: var(--ink); padding: 28px; }
.lead-form h3 { color: var(--navy); font-size: 1.22rem; margin-bottom: 18px; }
.form-row { display: grid; gap: 14px; grid-template-columns: 1fr 1fr; }
.field { margin-bottom: 14px; }
.field label { color: #475569; display: block; font-size: .8rem; font-weight: 600; margin-bottom: 5px; }
.field input, .field select, .field textarea { background: #f8fafc; border: 1px solid #cbd5e1; border-radius: 7px; color: var(--ink); font: inherit; font-size: .9rem; padding: 10px 12px; width: 100%; }
.field textarea { min-height: 92px; resize: vertical; }
.field input:focus, .field select:focus, .field textarea:focus { border-color: var(--teal); outline: 2px solid rgba(13,148,136,.12); }
.submit { background: var(--teal); border: 0; border-radius: 8px; color: #fff; cursor: pointer; font: inherit; font-weight: 700; padding: 13px 20px; width: 100%; }
.submit:hover { background: var(--teal-dark); }
.submit:disabled { cursor: wait; opacity: .65; }
.form-note, .form-status { color: var(--muted); font-size: .78rem; margin-top: 10px; text-align: center; }
.form-status.success { color: var(--teal-dark); }
.form-status.error { color: #b91c1c; }

.related-grid { display: grid; gap: 18px; grid-template-columns: repeat(3, minmax(0, 1fr)); }
.related-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); display: block; padding: 24px; }
.related-card:hover { border-color: var(--teal); box-shadow: 0 8px 25px rgba(13,148,136,.08); transform: translateY(-2px); }
.related-card h3 { color: var(--navy); font-size: 1rem; margin-bottom: 7px; }
.related-card p { color: var(--muted); font-size: .85rem; }

footer { background: #0b1120; color: #94a3b8; font-size: .86rem; padding: 28px 0; text-align: center; }
footer a:hover { color: #5eead4; }

@media (max-width: 800px) {
    .nav-links { display: none; }
    .hero { padding: 56px 0; }
    .section { padding: 52px 0; }
    .grid-2, .grid-3, .lead-grid, .related-grid { grid-template-columns: 1fr; }
    .checklist-grid, .form-row { grid-template-columns: 1fr; }
    .answer-box, .card, .checklist, .lead-form { padding: 22px; }
    .topic-nav { top: 70px; }
}