/* ===== qBittorrent 增强版 官网样式 ===== */
:root {
  --blue: #1f7aec;
  --blue-600: #1466d6;
  --blue-400: #3aa0ff;
  --ink: #0c1424;
  --ink-2: #1a2740;
  --slate: #51607a;
  --slate-2: #7b8aa5;
  --line: #e6ebf3;
  --bg: #ffffff;
  --bg-soft: #f5f8fd;
  --bg-dark: #0b1426;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 10px 40px rgba(17, 41, 86, .08);
  --shadow-lg: 0 24px 70px rgba(17, 41, 86, .16);
  --maxw: 1160px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
img, svg { display: block; }
.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.container.narrow { max-width: 820px; }

/* ===== 按钮 ===== */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 15px; font-weight: 600; line-height: 1;
  padding: 12px 20px; border-radius: 999px; border: 1.5px solid transparent;
  cursor: pointer; transition: transform .15s ease, box-shadow .2s ease, background .2s ease, color .2s ease;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }
.btn-primary {
  background: linear-gradient(135deg, var(--blue-400), var(--blue-600));
  color: #fff; box-shadow: 0 8px 22px rgba(31, 122, 236, .32);
}
.btn-primary:hover { box-shadow: 0 12px 30px rgba(31, 122, 236, .42); transform: translateY(-2px); }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--line); }
.btn-ghost:hover { border-color: var(--blue-400); color: var(--blue-600); }
.btn-sm { padding: 9px 16px; font-size: 14px; }
.btn-lg { padding: 15px 28px; font-size: 16px; }

/* ===== 顶部导航 ===== */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .82);
  backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color .25s ease, box-shadow .25s ease;
}
.site-header.scrolled { border-bottom-color: var(--line); box-shadow: 0 4px 20px rgba(17, 41, 86, .05); }
.nav { display: flex; align-items: center; height: 66px; gap: 24px; }
.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; font-size: 18px; letter-spacing: -.2px; }
.brand-text em { font-style: normal; color: var(--blue-600); }
.nav-links { display: flex; gap: 28px; margin-left: auto; }
.nav-links a { color: var(--slate); font-size: 15px; font-weight: 500; transition: color .15s; }
.nav-links a:hover { color: var(--ink); }
.nav-actions { display: flex; align-items: center; gap: 12px; margin-left: 8px; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; width: 40px; height: 40px; align-items: center; justify-content: center; background: none; border: 1px solid var(--line); border-radius: 10px; cursor: pointer; }
.nav-toggle span { width: 18px; height: 2px; background: var(--ink); border-radius: 2px; transition: .25s; }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===== 首屏 ===== */
.hero { position: relative; overflow: hidden; padding: 84px 0 72px; }
.hero-bg {
  position: absolute; inset: 0; z-index: -1;
  background:
    radial-gradient(1100px 520px at 78% -8%, rgba(58, 160, 255, .16), transparent 60%),
    radial-gradient(800px 480px at 8% 18%, rgba(31, 122, 236, .10), transparent 55%),
    linear-gradient(180deg, #fbfdff, #f4f8fe);
}
.hero-bg::after {
  content: ""; position: absolute; inset: 0;
  background-image: linear-gradient(var(--line) 1px, transparent 1px), linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 44px 44px; opacity: .35;
  mask-image: radial-gradient(700px 420px at 70% 10%, #000, transparent 75%);
}
.hero-inner { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.pill {
  display: inline-flex; align-items: center; gap: 8px;
  background: #fff; border: 1px solid var(--line); color: var(--blue-600);
  font-size: 13px; font-weight: 600; padding: 7px 14px; border-radius: 999px; box-shadow: var(--shadow);
}
.pill .dot { width: 7px; height: 7px; border-radius: 50%; background: #2bd37a; box-shadow: 0 0 0 4px rgba(43, 211, 122, .18); }
.hero h1 { font-size: clamp(34px, 5vw, 56px); line-height: 1.08; letter-spacing: -1.2px; margin: 22px 0 18px; font-weight: 850; }
.grad { background: linear-gradient(120deg, var(--blue-400), var(--blue-600)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.lead { font-size: 18px; color: var(--slate); max-width: 540px; }
.lead strong { color: var(--ink); font-weight: 700; }
.hero-cta { display: flex; gap: 14px; margin: 30px 0 22px; flex-wrap: wrap; }
.hero-trust { list-style: none; display: flex; flex-wrap: wrap; gap: 8px 22px; color: var(--slate); font-size: 14px; font-weight: 500; }
.hero-trust li { white-space: nowrap; }

/* 应用窗口示意 */
.hero-app { perspective: 1600px; }
.app-window {
  background: #fff; border-radius: 14px; box-shadow: var(--shadow-lg);
  border: 1px solid var(--line); overflow: hidden;
  transform: rotateY(-9deg) rotateX(3deg); transform-style: preserve-3d;
  transition: transform .4s ease;
}
.hero-app:hover .app-window { transform: rotateY(-4deg) rotateX(1deg); }
.app-titlebar { display: flex; align-items: center; gap: 7px; padding: 11px 14px; background: linear-gradient(180deg, #f7f9fc, #eef2f8); border-bottom: 1px solid var(--line); }
.tdot { width: 11px; height: 11px; border-radius: 50%; }
.tdot.r { background: #ff5f57; } .tdot.y { background: #febc2e; } .tdot.g { background: #28c840; }
.app-title { margin-left: 10px; font-size: 12.5px; color: var(--slate-2); font-weight: 600; }
.app-body { display: grid; grid-template-columns: 132px 1fr; min-height: 268px; }
.app-side { background: #f7f9fd; border-right: 1px solid var(--line); padding: 12px 10px; display: flex; flex-direction: column; gap: 4px; }
.side-item { font-size: 12.5px; color: var(--slate); padding: 7px 9px; border-radius: 8px; display: flex; justify-content: space-between; }
.side-item b { color: var(--ink); }
.side-item.active { background: rgba(31, 122, 236, .10); color: var(--blue-600); font-weight: 600; }
.app-main { padding: 14px 16px; display: flex; flex-direction: column; gap: 12px; }
.dl-row { display: grid; gap: 5px; }
.dl-name { font-size: 12.5px; font-weight: 600; color: var(--ink-2); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.dl-bar { height: 7px; background: #eef2f8; border-radius: 99px; overflow: hidden; }
.dl-bar i { display: block; height: 100%; background: linear-gradient(90deg, var(--blue-400), var(--blue-600)); border-radius: 99px; }
.dl-meta { display: flex; justify-content: space-between; font-size: 11.5px; color: var(--slate-2); }
.dl-meta .up { color: #2bd37a; font-weight: 600; }
.app-graph { margin-top: auto; position: relative; }
.app-graph svg { width: 100%; height: 60px; }
.graph-label { position: absolute; top: 0; right: 0; font-size: 11px; color: var(--slate-2); }

/* ===== 数据条 ===== */
.stats { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); background: var(--bg-soft); }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; padding: 36px 24px; text-align: center; }
.stats-grid b { display: block; font-size: 38px; font-weight: 850; letter-spacing: -1px; background: linear-gradient(120deg, var(--blue-400), var(--blue-600)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.stats-grid span { font-size: 14px; color: var(--slate); }

/* ===== 通用区块 ===== */
.section { padding: 88px 0; }
.section-alt { background: var(--bg-soft); }
.section-head { text-align: center; max-width: 680px; margin: 0 auto 52px; }
.eyebrow { display: inline-block; font-size: 13px; font-weight: 700; letter-spacing: .8px; text-transform: uppercase; color: var(--blue); margin-bottom: 12px; }
.section-head h2 { font-size: clamp(26px, 3.4vw, 38px); letter-spacing: -.8px; line-height: 1.18; font-weight: 820; }
.section-head p { margin-top: 14px; color: var(--slate); font-size: 17px; }

/* ===== 功能卡片 ===== */
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.feature-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px 24px; transition: transform .2s ease, box-shadow .2s ease, border-color .2s;
}
.feature-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: rgba(58, 160, 255, .5); }
.fc-icon { width: 48px; height: 48px; display: grid; place-items: center; font-size: 24px; border-radius: 12px; background: linear-gradient(135deg, rgba(58,160,255,.14), rgba(31,122,236,.10)); margin-bottom: 16px; }
.feature-card h3 { font-size: 18px; margin-bottom: 8px; letter-spacing: -.3px; }
.feature-card p { font-size: 14.5px; color: var(--slate); }

/* ===== 展示行 ===== */
.showcase-row { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.showcase-row + .showcase-row { margin-top: 72px; }
.showcase-row.reverse .showcase-text { order: 2; }
.showcase-text h2 { font-size: clamp(24px, 3vw, 32px); letter-spacing: -.6px; margin: 8px 0 14px; font-weight: 800; }
.showcase-text p { color: var(--slate); font-size: 16.5px; margin-bottom: 18px; }
.check-list { list-style: none; display: grid; gap: 11px; }
.check-list li { position: relative; padding-left: 30px; color: var(--ink-2); font-size: 15px; }
.check-list li::before { content: "✓"; position: absolute; left: 0; top: -1px; width: 20px; height: 20px; display: grid; place-items: center; font-size: 12px; font-weight: 800; color: #fff; background: linear-gradient(135deg, var(--blue-400), var(--blue-600)); border-radius: 50%; }
.showcase-visual { display: grid; place-items: center; }
.mini-card { width: 100%; max-width: 360px; background: linear-gradient(160deg, #fff, #f3f8ff); border: 1px solid var(--line); border-radius: 20px; padding: 28px; box-shadow: var(--shadow); }
.mc-head { font-size: 13px; color: var(--slate-2); font-weight: 600; }
.mc-speed { font-size: 44px; font-weight: 850; letter-spacing: -1.5px; margin: 4px 0 18px; color: var(--blue-600); }
.mc-speed small { font-size: 17px; color: var(--slate); font-weight: 600; }
.mc-bars { display: flex; align-items: flex-end; gap: 8px; height: 88px; }
.mc-bars i { flex: 1; background: linear-gradient(180deg, var(--blue-400), var(--blue-600)); border-radius: 6px 6px 0 0; opacity: .88; }
.mini-card.secure { text-align: center; }
.shield { font-size: 52px; margin-bottom: 14px; }
.mc-tags { display: flex; flex-wrap: wrap; gap: 9px; justify-content: center; margin-bottom: 14px; }
.mc-tags span { background: rgba(31,122,236,.10); color: var(--blue-600); font-size: 13px; font-weight: 600; padding: 6px 13px; border-radius: 999px; }
.mc-note { font-size: 13.5px; color: var(--slate); }

/* ===== 对比表 ===== */
.compare-wrap { overflow-x: auto; border-radius: var(--radius); box-shadow: var(--shadow); border: 1px solid var(--line); }
.compare-table { width: 100%; border-collapse: collapse; background: #fff; min-width: 560px; }
.compare-table th, .compare-table td { padding: 16px 22px; text-align: left; font-size: 15px; border-bottom: 1px solid var(--line); }
.compare-table thead th { background: #fafcff; font-weight: 700; color: var(--ink); }
.compare-table th.hl, .compare-table td.hl { background: linear-gradient(180deg, rgba(31,122,236,.06), rgba(31,122,236,.03)); color: var(--ink); font-weight: 600; }
.compare-table thead th.hl { color: var(--blue-600); }
.compare-table td:first-child { color: var(--slate); font-weight: 600; }
.compare-table tr:last-child td { border-bottom: none; }

/* ===== 下载 ===== */
.download-tabs { max-width: 820px; margin: 0 auto; }
.tab-btns { display: inline-flex; gap: 4px; padding: 5px; background: #fff; border: 1px solid var(--line); border-radius: 999px; margin: 0 auto 28px; box-shadow: var(--shadow); }
.tab-btns { display: flex; width: max-content; margin-left: auto; margin-right: auto; }
.tab-btn { border: none; background: transparent; padding: 10px 24px; border-radius: 999px; font-size: 15px; font-weight: 600; color: var(--slate); cursor: pointer; transition: .2s; }
.tab-btn.active { background: linear-gradient(135deg, var(--blue-400), var(--blue-600)); color: #fff; }
.tab-panel { display: none; }
.tab-panel.active { display: block; animation: fade .35s ease; }
.dl-cards { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.dl-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; text-align: center; transition: border-color .2s, box-shadow .2s; }
.dl-card:hover { border-color: rgba(58,160,255,.5); box-shadow: var(--shadow); }
.dl-card h4 { font-size: 18px; margin-bottom: 6px; }
.dl-card p { font-size: 14px; color: var(--slate); margin-bottom: 18px; min-height: 42px; }
.dl-foot { text-align: center; font-size: 13.5px; color: var(--slate-2); margin-top: 24px; }
.dl-foot a { color: var(--blue-600); font-weight: 600; }

/* ===== FAQ ===== */
.faq-list { display: grid; gap: 12px; }
.faq-item { background: #fff; border: 1px solid var(--line); border-radius: var(--radius-sm); overflow: hidden; }
.faq-item summary { list-style: none; cursor: pointer; padding: 18px 22px; font-weight: 650; font-size: 16px; display: flex; justify-content: space-between; align-items: center; gap: 16px; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; font-size: 22px; font-weight: 400; color: var(--blue); transition: transform .25s; flex-shrink: 0; }
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-body { padding: 0 22px 18px; color: var(--slate); font-size: 15px; }

/* ===== CTA 带 ===== */
.cta-band { background: linear-gradient(135deg, #0e1f3d, #123a78); color: #fff; padding: 72px 0; position: relative; overflow: hidden; }
.cta-band::before { content: ""; position: absolute; inset: 0; background: radial-gradient(700px 360px at 80% 0%, rgba(58,160,255,.35), transparent 60%); }
.cta-inner { text-align: center; position: relative; }
.cta-inner h2 { font-size: clamp(26px, 3.4vw, 36px); letter-spacing: -.6px; font-weight: 820; }
.cta-inner p { color: rgba(255,255,255,.8); font-size: 17px; margin: 14px 0 28px; }

/* ===== 页脚 ===== */
.site-footer { background: var(--bg-dark); color: #aab6cc; padding: 56px 0 28px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 32px; padding-bottom: 36px; border-bottom: 1px solid rgba(255,255,255,.08); }
.footer-brand .brand { color: #fff; margin-bottom: 14px; }
.footer-brand .brand-text em { color: var(--blue-400); }
.footer-brand p { font-size: 14px; max-width: 320px; }
.footer-col h5 { color: #fff; font-size: 14px; margin-bottom: 14px; letter-spacing: .3px; }
.footer-col a { display: block; font-size: 14px; padding: 5px 0; color: #aab6cc; transition: color .15s; }
.footer-col a:hover { color: #fff; }
.footer-bottom { padding-top: 24px; font-size: 13px; color: #6b7896; line-height: 1.75; }
.footer-bottom p { margin: 2px 0; }
.footer-bottom a { color: #8fa0bd; transition: color .15s; }
.footer-bottom a:hover { color: #fff; }

/* ===== 滚动揭示动画 ===== */
.reveal { opacity: 0; transform: translateY(22px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }
@keyframes fade { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }
@media (prefers-reduced-motion: reduce) { .reveal { opacity: 1; transform: none; transition: none; } html { scroll-behavior: auto; } }

/* ===== 响应式 ===== */
@media (max-width: 920px) {
  .hero-inner { grid-template-columns: 1fr; gap: 40px; }
  .hero-app { max-width: 480px; }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .showcase-row { grid-template-columns: 1fr; gap: 28px; }
  .showcase-row.reverse .showcase-text { order: 0; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 680px) {
  .nav-links { position: fixed; inset: 66px 0 auto 0; background: #fff; flex-direction: column; gap: 0; padding: 12px 24px 20px; border-bottom: 1px solid var(--line); box-shadow: var(--shadow); transform: translateY(-130%); transition: transform .3s ease; }
  .nav-links.open { transform: translateY(0); }
  .nav-links a { padding: 13px 0; border-bottom: 1px solid var(--line); font-size: 16px; }
  .nav-toggle { display: flex; }
  .nav-links { margin-left: 0; }
  .stats-grid { grid-template-columns: 1fr 1fr; gap: 28px 16px; }
  .feature-grid { grid-template-columns: 1fr; }
  .dl-cards { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 26px; }
  .section { padding: 64px 0; }
  .hero { padding: 56px 0 48px; }
}