:root {
  --brand: #3B6EF6;
  --brand-soft: #EAF1FE;
  --ink: #1A1A1A;
  --ink-2: #5A6270;
  --ink-3: #8A8F99;
  --line: #ECEDF1;
  --card: #FFFFFF;
  --bg: #F6F7F9;
  --radius: 18px;
  --shadow: 0 2px 10px rgba(23, 33, 56, 0.05);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { -webkit-text-size-adjust: 100%; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.65;
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap { width: 100%; max-width: 920px; margin: 0 auto; padding: 0 20px; }

/* ---------- 顶栏 ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}

.topbar-in {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 700;
  font-size: 16px;
  letter-spacing: 0.2px;
  color: var(--ink);
}
.brand:hover { text-decoration: none; }

.brand-mark {
  width: 26px;
  height: 26px;
  border-radius: 8px;
  background: var(--brand);
  display: grid;
  place-items: center;
  color: #fff;
  font-size: 13px;
  font-weight: 700;
}

.nav { display: flex; gap: 22px; }
.nav a { color: var(--ink-2); font-size: 14px; }
.nav a:hover { color: var(--brand); text-decoration: none; }

@media (max-width: 560px) {
  .nav { gap: 14px; }
  .nav a { font-size: 13px; }
}

/* ---------- Hero ---------- */
.hero { padding: 56px 0 40px; }

.hero h1 {
  font-size: 34px;
  line-height: 1.28;
  letter-spacing: -0.5px;
  font-weight: 800;
}

.hero .lead {
  margin-top: 14px;
  font-size: 16px;
  color: var(--ink-2);
  max-width: 620px;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 32px;
  padding: 0 14px;
  border-radius: 16px;
  background: var(--brand-soft);
  color: #2A56C6;
  font-size: 13px;
  font-weight: 600;
}

.pill-plain {
  background: #fff;
  color: var(--ink-2);
  border: 1px solid var(--line);
  font-weight: 500;
}

@media (max-width: 560px) {
  .hero { padding: 36px 0 28px; }
  .hero h1 { font-size: 26px; }
  .hero .lead { font-size: 15px; }
}

/* ---------- 区块 ---------- */
.section { padding: 14px 0 8px; }

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin: 26px 0 14px;
}

.section-title { font-size: 19px; font-weight: 700; letter-spacing: -0.2px; }
.section-note { font-size: 13px; color: var(--ink-3); }

/* ---------- 分类卡 ---------- */
.cats {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px;
}

.cat {
  background: var(--card);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: var(--shadow);
  border: 1px solid rgba(236, 237, 241, 0.9);
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.cat:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 22px rgba(23, 33, 56, 0.09);
}

.cat-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.cat-name { font-size: 15px; font-weight: 700; }

.cat-num {
  font-size: 12px;
  color: var(--brand);
  background: var(--brand-soft);
  border-radius: 9px;
  padding: 1px 8px;
  font-weight: 700;
}

.cat-list { font-size: 13px; color: var(--ink-3); line-height: 1.7; }

/* ---------- 特性 ---------- */
.feats {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: 12px;
  margin-top: 6px;
}

.feat {
  background: var(--card);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: var(--shadow);
  border: 1px solid rgba(236, 237, 241, 0.9);
}

.feat h3 { font-size: 15px; font-weight: 700; margin-bottom: 6px; }
.feat p { font-size: 13.5px; color: var(--ink-2); }

/* ---------- 隐私条 ---------- */
.privacy-band {
  margin: 30px 0 10px;
  background: #fff;
  border: 1px solid var(--line);
  border-left: 3px solid var(--brand);
  border-radius: 14px;
  padding: 18px 20px;
}

.privacy-band h3 { font-size: 15px; margin-bottom: 6px; }
.privacy-band p { font-size: 13.5px; color: var(--ink-2); }

/* ---------- FAQ ---------- */
.faq { margin-top: 4px; }

details {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 14px 18px;
  margin-bottom: 10px;
}

details summary {
  cursor: pointer;
  font-weight: 600;
  font-size: 14.5px;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

details summary::-webkit-details-marker { display: none; }

details summary::after {
  content: "+";
  color: var(--ink-3);
  font-weight: 400;
  font-size: 18px;
  line-height: 1;
}

details[open] summary::after { content: "\2212"; }

details p { margin-top: 10px; font-size: 14px; color: var(--ink-2); }

/* ---------- 页脚 ---------- */
.footer {
  margin-top: 46px;
  border-top: 1px solid var(--line);
  padding: 26px 0 40px;
  font-size: 13px;
  color: var(--ink-3);
}

.footer-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  align-items: center;
  justify-content: space-between;
}

.footer-links { display: flex; gap: 18px; flex-wrap: wrap; }

/* ---------- 文档页（隐私政策） ---------- */
.doc {
  background: #fff;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  padding: 34px 34px 30px;
  margin: 28px 0 10px;
  box-shadow: var(--shadow);
}

.doc h1 { font-size: 25px; letter-spacing: -0.3px; margin-bottom: 6px; }
.doc .updated { font-size: 13px; color: var(--ink-3); margin-bottom: 24px; }
.doc h2 {
  font-size: 16.5px;
  margin: 26px 0 8px;
  padding-top: 4px;
}
.doc h3 { font-size: 14.5px; margin: 16px 0 6px; color: var(--ink-2); }
.doc p { font-size: 14.5px; color: #33383F; margin-bottom: 9px; }
.doc ul { margin: 6px 0 10px 20px; }
.doc li { font-size: 14.5px; color: #33383F; margin-bottom: 5px; }

.doc table {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0 14px;
  font-size: 13.5px;
}

.doc th, .doc td {
  text-align: left;
  padding: 9px 10px;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
  color: #33383F;
}

.doc th { background: #FAFBFC; font-weight: 600; color: var(--ink); }

.doc code {
  background: #F2F4F7;
  border-radius: 5px;
  padding: 1px 5px;
  font-size: 13px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.callout {
  background: #F7F9FF;
  border: 1px solid #E2EAFB;
  border-radius: 12px;
  padding: 14px 16px;
  margin: 14px 0;
}

.callout p { margin: 0; font-size: 13.5px; color: #2A56C6; }

@media (max-width: 560px) {
  .doc { padding: 22px 18px; border-radius: 14px; }
  .doc h1 { font-size: 21px; }
  .doc table { font-size: 12.5px; }
  .doc th, .doc td { padding: 7px 6px; }
}

/* ---------- 404 ---------- */
.err {
  min-height: 62vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 40px 0;
}

.err-code { font-size: 56px; font-weight: 800; color: var(--brand); letter-spacing: -2px; }
.err h1 { font-size: 19px; margin: 10px 0 8px; }
.err p { color: var(--ink-2); font-size: 14px; margin-bottom: 20px; }

.btn {
  display: inline-flex;
  align-items: center;
  height: 40px;
  padding: 0 20px;
  border-radius: 20px;
  background: var(--brand);
  color: #fff;
  font-size: 14px;
  font-weight: 600;
}

.btn:hover { text-decoration: none; opacity: 0.92; }