:root {
    --bbc-red: #b8001f;
    --bbc-red-dark: #7f0016;
    --ink: #172033;
    --muted: #5f6b7a;
    --line: #e3e8ef;
    --soft: #f6f8fb;
    --warm: #fff5f5;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: #fff; font-family: "Outfit", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif; line-height: 1.78; }
img { max-width: 100%; }
a { color: var(--bbc-red); }
.page-container { width: min(1120px, calc(100% - 32px)); margin: 0 auto; }
.top-nav { position: sticky; top: 0; z-index: 1000; min-height: 66px; padding: 10px 30px; display: flex; align-items: center; justify-content: space-between; gap: 22px; background: rgba(255,255,255,.97); border-bottom: 1px solid var(--line); box-shadow: 0 2px 12px rgba(15,23,42,.05); }
.nav-brand { color: var(--ink); text-decoration: none; font-weight: 850; white-space: nowrap; }
.nav-brand span { color: var(--bbc-red); }
.nav-links { display: flex; align-items: center; justify-content: center; flex-wrap: wrap; gap: 18px; }
.nav-links a { color: #526174; text-decoration: none; font-size: .93rem; white-space: nowrap; }
.nav-links a:hover, .nav-links a.active { color: var(--bbc-red); font-weight: 750; }
.nav-links .xiaohongshu { color: #ff2442; }
.nav-cta { padding: 9px 15px; color: #fff; background: var(--bbc-red); border-radius: 9px; text-decoration: none; font-weight: 750; white-space: nowrap; }
.hero { padding: 88px 0 72px; background: linear-gradient(145deg, #fff 0%, #fff5f6 58%, #fbe8ec 100%); }
.hero-grid { display: grid; grid-template-columns: 1.05fr .95fr; gap: 52px; align-items: center; }
.eyebrow { display: inline-flex; padding: 6px 12px; color: var(--bbc-red-dark); background: #fde7eb; border-radius: 999px; font-weight: 750; }
h1 { margin: 18px 0; font-size: clamp(2.2rem, 5vw, 4rem); line-height: 1.1; letter-spacing: -.025em; }
.hero p { max-width: 680px; color: #465569; font-size: 1.07rem; }
.hero img { display: block; width: 100%; border-radius: 24px; box-shadow: 0 24px 58px rgba(127,0,22,.16); }
.source-note { color: var(--muted); font-size: .86rem !important; }
.section { padding: 74px 0; }
.section.alt { background: var(--soft); }
.section-title { max-width: 780px; margin: 0 auto 38px; text-align: center; }
.section-title h2, .content-copy h2 { margin: 0 0 12px; font-size: clamp(1.75rem, 3vw, 2.55rem); line-height: 1.25; }
.section-title p, .content-copy p { color: var(--muted); }
.grid-2, .grid-3, .grid-4 { display: grid; gap: 22px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.card { padding: 25px; background: #fff; border: 1px solid var(--line); border-radius: 18px; box-shadow: 0 12px 30px rgba(15,23,42,.055); }
.card h3 { margin: 0 0 10px; }
.card p { margin: 0; color: var(--muted); }
.badge { display: inline-flex; padding: 5px 10px; color: var(--bbc-red-dark); background: #fde7eb; border-radius: 999px; font-size: .8rem; font-weight: 750; }
.content-row { display: grid; grid-template-columns: 1fr 1fr; gap: 46px; align-items: center; }
.content-row img { width: 100%; border-radius: 22px; box-shadow: 0 18px 42px rgba(15,23,42,.12); }
.check-list { margin: 20px 0 0; padding-left: 20px; }
.check-list li { margin: 9px 0; }
.note { padding: 27px 30px; background: var(--warm); border-left: 5px solid var(--bbc-red); border-radius: 16px; }
.note h2, .note h3 { margin-top: 0; }
.note p:last-child { margin-bottom: 0; }
.step { display: grid; grid-template-columns: 44px 1fr; gap: 14px; align-items: start; padding: 20px; background: #fff; border: 1px solid var(--line); border-radius: 16px; }
.step-number { width: 44px; height: 44px; display: grid; place-items: center; color: #fff; background: var(--bbc-red); border-radius: 50%; font-weight: 800; }
.step h3 { margin: 2px 0 6px; }
.step p { margin: 0; color: var(--muted); }
.source-list { padding-left: 22px; }
.source-list li { margin: 8px 0; }
.comparison { width: 100%; border-collapse: collapse; background: #fff; border: 1px solid var(--line); border-radius: 16px; overflow: hidden; }
.comparison th, .comparison td { padding: 15px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
.comparison th { background: #f9e9ec; }
.button-row { display: flex; flex-wrap: wrap; justify-content: center; gap: 14px; margin-top: 28px; }
.button { display: inline-flex; padding: 11px 18px; border-radius: 9px; text-decoration: none; font-weight: 750; }
.button.primary { color: #fff; background: var(--bbc-red); }
.button.secondary { color: var(--bbc-red); background: #fff; border: 1px solid #e7a9b5; }
footer { padding: 38px 16px 82px; color: #c9d1dc; background: #111827; text-align: center; }
.home-return-btn { position: fixed; right: 20px; bottom: 20px; z-index: 900; padding: 10px 15px; color: #fff; background: #334155; border-radius: 999px; text-decoration: none; box-shadow: 0 8px 24px rgba(15,23,42,.28); }

@media (max-width: 960px) {
    .top-nav { padding: 12px 16px; flex-wrap: wrap; }
    .nav-links { order: 3; width: 100%; gap: 11px; }
    .hero-grid, .content-row { grid-template-columns: 1fr; }
    .grid-4 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 680px) {
    .hero { padding: 54px 0 46px; }
    .section { padding: 50px 0; }
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
    .comparison { display: block; overflow-x: auto; }
    .nav-cta { font-size: .83rem; }
}