:root {
    color-scheme: light;
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-bg: #eff6ff;
    --hero-bg: linear-gradient(180deg, #eff6ff 0%, #fff 100%);
    --bg: #ffffff;
    --bg-gray: #f8fafc;
    --text: #1f2937;
    --text-secondary: #6b7280;
    --border: #e5e7eb;
    --card-bg: #ffffff;
    --code-bg: #f3f4f6;
    --footer-bg: #111827;
    --footer-text: #9ca3af;
    --radius: 8px;
    --shadow: 0 2px 12px rgba(0,0,0,.06);
    --shadow-hover: 0 8px 24px rgba(0,0,0,.08);
    --gradient: linear-gradient(135deg, #2563eb, #3b82f6);
}
[data-theme="dark"] {
    color-scheme: dark;
    --primary: #3b82f6;
    --primary-dark: #2563eb;
    --primary-bg: #1e3a5f;
    --hero-bg: linear-gradient(180deg, #1e293b 0%, #0f172a 100%);
    --bg: #0f172a;
    --bg-gray: #111c33;
    --text: #e2e8f0;
    --text-secondary: #94a3b8;
    --border: #2b3a55;
    --card-bg: #1b2740;
    --code-bg: #25324d;
    --footer-bg: #0b1222;
    --footer-text: #94a3b8;
    --shadow: 0 2px 12px rgba(0,0,0,.35);
    --shadow-hover: 0 8px 24px rgba(0,0,0,.45);
    --gradient: linear-gradient(135deg, #3b82f6, #60a5fa);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif; color: var(--text); font-size: 15px; line-height: 1.7; background: var(--bg); transition: background .25s, color .25s; }
a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-dark); }
img { max-width: 100%; }
.container { max-width: 1120px; margin: 0 auto; padding: 0 20px; }

/* 顶部导航 */
.site-header { position: sticky; top: 0; z-index: 100; background: rgba(255,255,255,.92); backdrop-filter: blur(8px); border-bottom: 1px solid var(--border); transition: background .25s; }
[data-theme="dark"] .site-header { background: rgba(15,23,42,.92); }
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo { display: flex; align-items: center; gap: 10px; font-size: 20px; font-weight: 700; }
.logo .logo-mark { width: 34px; height: 34px; border-radius: 8px; background: var(--gradient); color: #fff; display: flex; align-items: center; justify-content: center; font-size: 16px; }
.nav-links { display: flex; align-items: center; gap: 26px; font-size: 15px; }
.nav-links a { color: var(--text); }
.nav-links a:hover, .nav-links a.active { color: var(--primary); }
.nav-btn { background: var(--primary); color: #fff !important; padding: 8px 20px; border-radius: 6px; }
.nav-btn:hover { background: var(--primary-dark); color: #fff !important; }
.theme-btn { width: 34px; height: 34px; border: 1px solid var(--border); border-radius: 50%; background: transparent; color: var(--text-secondary); cursor: pointer; display: inline-flex; align-items: center; justify-content: center; transition: color .2s, border-color .2s; }
.theme-btn:hover { color: var(--primary); border-color: var(--primary); }
.theme-btn svg { width: 17px; height: 17px; }
.theme-btn .icon-sun { display: none; }
[data-theme="dark"] .theme-btn .icon-sun { display: block; }
[data-theme="dark"] .theme-btn .icon-moon { display: none; }

/* Hero */
.hero { background: var(--hero-bg); padding: 80px 0 70px; text-align: center; }
.hero h1 { font-size: 40px; font-weight: 700; letter-spacing: 1px; }
.hero .slogan { color: var(--primary); font-size: 18px; margin-top: 8px; }
.hero p.sub { color: var(--text-secondary); max-width: 640px; margin: 20px auto 0; font-size: 16px; }
.hero .actions { margin-top: 32px; display: flex; gap: 16px; justify-content: center; }
.btn { display: inline-block; padding: 11px 28px; border-radius: 6px; font-size: 15px; border: none; cursor: pointer; transition: background .2s, color .2s, border-color .2s; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); color: #fff; }
.btn-outline { background: var(--card-bg); color: var(--primary); border: 1px solid var(--primary); }
.btn-outline:hover { background: var(--primary-bg); color: var(--primary); }

/* 区块 */
.section { padding: 64px 0; }
.section-gray { background: var(--bg-gray); }
.section-head { text-align: center; margin-bottom: 40px; }
.section-head h2 { font-size: 28px; }
.section-head p { color: var(--text-secondary); margin-top: 8px; }

/* 特性 */
.features { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.feature { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; transition: box-shadow .2s, transform .2s; }
.feature:hover { box-shadow: var(--shadow); transform: translateY(-2px); }
.feature .icon { width: 44px; height: 44px; border-radius: 10px; background: var(--primary-bg); color: var(--primary); display: flex; align-items: center; justify-content: center; font-size: 20px; margin-bottom: 14px; }
.feature h3 { font-size: 17px; margin-bottom: 8px; }
.feature p { color: var(--text-secondary); font-size: 14px; }

/* 业务介绍 */
.biz-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.biz-card { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 26px 24px; display: flex; flex-direction: column; transition: box-shadow .2s, transform .2s; }
.biz-card:hover { box-shadow: var(--shadow-hover); transform: translateY(-2px); }
.biz-card .icon { width: 48px; height: 48px; border-radius: 12px; background: var(--gradient); color: #fff; display: flex; align-items: center; justify-content: center; font-size: 20px; margin-bottom: 16px; }
.biz-card h3 { font-size: 18px; margin-bottom: 8px; }
.biz-card .summary { color: var(--primary); font-size: 14px; margin-bottom: 10px; }
.biz-card .desc { color: var(--text-secondary); font-size: 14px; flex: 1; margin-bottom: 18px; }
.biz-card .btn { align-self: flex-start; padding: 8px 22px; font-size: 14px; }

/* 产品 */
.products { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 20px; }
.product { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 26px 22px; display: flex; flex-direction: column; position: relative; transition: box-shadow .2s; }
.product:hover { box-shadow: var(--shadow-hover); }
.product.hot { border-color: var(--primary); box-shadow: 0 0 0 1px var(--primary); }
.product .tag-hot { position: absolute; top: -11px; right: 16px; background: var(--primary); color: #fff; font-size: 12px; padding: 2px 10px; border-radius: 10px; }
.product h3 { font-size: 16px; }
.product .price { margin: 14px 0 4px; }
.product .price .num { font-size: 30px; font-weight: 700; color: var(--primary); }
.product .price .unit { color: var(--text-secondary); font-size: 13px; margin-left: 2px; }
.product .meta { color: var(--text-secondary); font-size: 13px; margin-bottom: 12px; }
.product .desc { color: var(--text-secondary); font-size: 13px; flex: 1; margin-bottom: 18px; }
.product .btn { text-align: center; }

/* 流程 */
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; counter-reset: step; }
.step { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px; transition: box-shadow .2s; }
.step:hover { box-shadow: var(--shadow); }
.step .no { width: 32px; height: 32px; border-radius: 50%; background: var(--primary); color: #fff; display: flex; align-items: center; justify-content: center; font-weight: 700; margin-bottom: 12px; }
.step h4 { font-size: 15px; margin-bottom: 6px; }
.step p { color: var(--text-secondary); font-size: 13px; }

/* 联系方式 */
.contacts { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.contact { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px; text-align: center; transition: box-shadow .2s; }
.contact:hover { box-shadow: var(--shadow); }
.contact .icon { font-size: 26px; margin-bottom: 10px; }
.contact h4 { font-size: 14px; color: var(--text-secondary); margin-bottom: 6px; }
.contact .val { font-size: 16px; font-weight: 600; word-break: break-all; }

/* 页脚 */
.site-footer { background: var(--footer-bg); color: var(--footer-text); padding: 36px 0 30px; font-size: 13px; }
.site-footer .container { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 16px; }
.site-footer a { color: var(--footer-text); }
.site-footer a:hover { color: #fff; }
.site-footer .links { display: flex; gap: 20px; }

/* 公告 */
.notice { background: #fffbeb; border: 1px solid #fde68a; color: #92400e; border-radius: var(--radius); padding: 12px 16px; margin: 24px 0; font-size: 14px; }
[data-theme="dark"] .notice { background: #3a3320; border-color: #66572f; color: #f0dfa8; }

/* 页面主体 */
.page { padding: 48px 0 64px; }
.page-title { text-align: center; margin-bottom: 36px; }
.page-title h1 { font-size: 30px; }
.page-title p { color: var(--text-secondary); margin-top: 8px; }
.card { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; margin-bottom: 20px; box-shadow: var(--shadow); }
.card h3 { font-size: 18px; margin-bottom: 14px; }
.card h4 { font-size: 15px; margin: 16px 0 8px; }
.card p { color: var(--text-secondary); font-size: 14px; margin-bottom: 10px; }
.card ul { padding-left: 20px; color: var(--text-secondary); font-size: 14px; }
.card li { margin-bottom: 6px; }
.card code { background: var(--code-bg); border: 1px solid var(--border); padding: 1px 6px; border-radius: 4px; font-size: 13px; color: #d97706; }
[data-theme="dark"] .card code { color: #fbbf24; }
.card pre { background: #0f172a; color: #e5e7eb; border-radius: 6px; padding: 14px 16px; font-size: 13px; overflow-x: auto; margin: 10px 0; line-height: 1.6; }
.card pre code { background: none; border: none; padding: 0; color: inherit; }

/* 使用指南 */
.guide-wrap { display: grid; grid-template-columns: 220px 1fr; gap: 28px; align-items: start; }
.guide-side { position: sticky; top: 84px; }
.guide-main { min-width: 0; }
.guide-nav { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 12px; box-shadow: var(--shadow); }
.guide-nav .guide-title { font-size: 13px; color: var(--text-secondary); padding: 6px 12px 10px; font-weight: 700; border-bottom: 1px dashed var(--border); margin-bottom: 6px; }
.guide-nav a { display: block; padding: 8px 12px; border-radius: 6px; color: var(--text-secondary); font-size: 14px; transition: background .15s, color .15s; }
.guide-nav a:hover { color: var(--primary); background: var(--primary-bg); }
.guide-nav a.active { color: var(--primary); background: var(--primary-bg); font-weight: 600; }
.guide-main .card { scroll-margin-top: 84px; }
.guide-main .card h3 { display: flex; align-items: center; gap: 10px; }
.guide-main .card h3 .sec-no { width: 26px; height: 26px; border-radius: 8px; background: var(--gradient); color: #fff; font-size: 13px; display: inline-flex; align-items: center; justify-content: center; flex-shrink: 0; }
.dl-box { display: flex; align-items: center; gap: 16px; background: var(--primary-bg); border: 1px dashed var(--primary); border-radius: var(--radius); padding: 14px 16px; margin: 12px 0; flex-wrap: wrap; }
.dl-box .dl-info { flex: 1; min-width: 200px; }
.dl-box .dl-info .t { font-weight: 600; color: var(--text); }
.dl-box .dl-info .d { color: var(--text-secondary); font-size: 13px; }

/* 表单 */
.form-group { margin-bottom: 16px; }
.form-group label { display: block; margin-bottom: 6px; font-weight: 500; font-size: 14px; }
.form-control { width: 100%; padding: 10px 12px; border: 1px solid var(--border); border-radius: 6px; font-size: 14px; background: var(--card-bg); color: var(--text); }
.form-control:focus { outline: none; border-color: var(--primary); }
.form-hint { color: var(--text-secondary); font-size: 12px; margin-top: 4px; }
.refund-tip { background: #fef2f2; border: 1px solid #fecaca; color: #b91c1c; border-radius: var(--radius); padding: 12px 16px; font-size: 14px; margin-bottom: 16px; line-height: 1.6; }
[data-theme="dark"] .refund-tip { background: #3b1517; border-color: #6b2b2e; color: #fca5a5; }
.form-error { background: #fef2f2; border: 1px solid #fecaca; color: #b91c1c; border-radius: var(--radius); padding: 12px 16px; font-size: 14px; margin-bottom: 16px; }
[data-theme="dark"] .form-error { background: #3b1517; border-color: #6b2b2e; color: #fca5a5; }

/* 订单确认弹窗 */
.confirm-mask { position: fixed; inset: 0; background: rgba(0,0,0,.5); z-index: 1000; display: none; align-items: center; justify-content: center; }
.confirm-box { background: var(--card-bg); border-radius: 10px; width: 440px; max-width: 92vw; padding: 26px; box-shadow: var(--shadow-hover); }
.confirm-box h3 { font-size: 18px; margin-bottom: 16px; }
.confirm-table { width: 100%; border-collapse: collapse; font-size: 14px; }
.confirm-table td { padding: 9px 4px; border-bottom: 1px solid var(--border); vertical-align: top; }
.confirm-table .k { color: var(--text-secondary); width: 84px; }
.confirm-table .v { word-break: break-all; }
.confirm-refund { background: #fef2f2; border: 1px solid #fecaca; color: #b91c1c; border-radius: var(--radius); padding: 10px 14px; font-size: 13px; margin: 14px 0; line-height: 1.6; }
[data-theme="dark"] .confirm-refund { background: #3b1517; border-color: #6b2b2e; color: #fca5a5; }
.confirm-actions { display: flex; gap: 12px; margin-top: 18px; }
.confirm-actions .btn { flex: 1; text-align: center; }

/* 购买页 */
.buy-wrap { max-width: 720px; margin: 0 auto; }
.product-radio { border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 18px; margin-bottom: 12px; cursor: pointer; display: flex; justify-content: space-between; align-items: center; transition: border-color .2s, background .2s; background: var(--card-bg); }
.product-radio.selected { border-color: var(--primary); background: var(--primary-bg); }
.product-radio .name { font-weight: 600; }
.product-radio .meta { color: var(--text-secondary); font-size: 13px; }
.product-radio .price { color: var(--primary); font-weight: 700; font-size: 18px; }

/* 结果页 */
.result-box { max-width: 480px; margin: 60px auto; text-align: center; }
.result-box .icon { width: 64px; height: 64px; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 30px; margin: 0 auto 18px; }
.result-box .icon.ok { background: #f6ffed; color: #52c41a; }
[data-theme="dark"] .result-box .icon.ok { background: #16351f; }
.result-box .icon.fail { background: #fff1f0; color: #ff4d4f; }
[data-theme="dark"] .result-box .icon.fail { background: #3b1517; }
.result-box h2 { font-size: 22px; margin-bottom: 10px; }
.result-box p { color: var(--text-secondary); margin-bottom: 8px; }
.result-box .btn { margin-top: 20px; }

@media (max-width: 768px) {
    .hero h1 { font-size: 30px; }
    .features, .steps, .contacts, .biz-grid { grid-template-columns: 1fr 1fr; }
    .guide-wrap { grid-template-columns: 150px 1fr; gap: 14px; }
    .guide-side { top: 72px; }
    .guide-nav a { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
    .nav-links { gap: 14px; font-size: 14px; }
    .nav-links .nav-btn { padding: 6px 12px; }
    .nav-links .guide-hide { display: none; }
}