:root {
  --bg: #f7f8fa;
  --surface: #ffffff;
  --surface-2: #f1f3f5;
  --border: #e5e7eb;
  --fg: #1c1c22;
  --muted: #6b7280;
  --accent: #0a6cff;
  --accent-soft: rgba(10, 108, 255, 0.1);
  --radius: 16px;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.04), 0 8px 24px rgba(0, 0, 0, 0.06);
  --maxw: 880px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0e0f12;
    --surface: #17181c;
    --surface-2: #1f2127;
    --border: #2a2d34;
    --fg: #ececef;
    --muted: #9aa0aa;
    --accent: #4d97ff;
    --accent-soft: rgba(77, 151, 255, 0.14);
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 8px 24px rgba(0, 0, 0, 0.4);
  }
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei',
    Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

/* 顶栏 */
.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(10px);
  background: color-mix(in srgb, var(--bg) 80%, transparent);
  border-bottom: 1px solid var(--border);
}
.nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  color: var(--fg);
}
.brand img {
  width: 28px;
  height: 28px;
  border-radius: 8px;
}
.nav-links {
  display: flex;
  gap: 22px;
  align-items: center;
  font-size: 15px;
}
.nav-links a {
  color: var(--muted);
}
.nav-links a:hover {
  color: var(--fg);
  text-decoration: none;
}

/* 氛围光 hero */
.hero {
  position: relative;
  overflow: hidden;
  text-align: center;
  padding: 96px 0 72px;
}
.hero::before {
  content: '';
  position: absolute;
  top: -180px;
  left: 50%;
  transform: translateX(-50%);
  width: 720px;
  height: 360px;
  background: var(--accent);
  opacity: 0.14;
  filter: blur(120px);
  border-radius: 50%;
  pointer-events: none;
}
.hero .logo {
  width: 76px;
  height: 76px;
  border-radius: 22px;
  border: 1px solid var(--border);
  background: var(--surface);
  box-shadow: var(--shadow);
  display: grid;
  place-items: center;
  margin: 0 auto 22px;
}
.hero .logo img {
  width: 46px;
  height: 46px;
}
.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 12px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--muted);
  font-size: 13px;
  font-weight: 500;
}
.badge .dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent);
}
.hero h1 {
  font-size: clamp(34px, 6vw, 52px);
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin: 18px 0 12px;
}
.hero p.lead {
  max-width: 560px;
  margin: 0 auto 28px;
  color: var(--muted);
  font-size: 18px;
}
.cta {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 15px;
  border: 1px solid transparent;
  cursor: pointer;
}
.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover {
  filter: brightness(1.05);
  text-decoration: none;
}
.btn-ghost {
  background: var(--surface);
  border-color: var(--border);
  color: var(--fg);
}
.btn-ghost:hover {
  border-color: var(--accent);
  text-decoration: none;
}

/* 区块 */
section.block {
  padding: 56px 0;
}
section.block h2 {
  font-size: 26px;
  letter-spacing: -0.01em;
  margin: 0 0 6px;
}
section.block .sub {
  color: var(--muted);
  margin: 0 0 32px;
}

/* 特性网格 */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}
.card {
  position: relative;
  border: 1px solid var(--border);
  background: var(--surface);
  border-radius: var(--radius);
  padding: 22px;
  transition: transform 0.2s, border-color 0.2s, box-shadow 0.2s;
}
.card:hover {
  transform: translateY(-3px);
  border-color: color-mix(in srgb, var(--accent) 40%, var(--border));
  box-shadow: var(--shadow);
}
.card .ico {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  background: var(--accent-soft);
  color: var(--accent);
  display: grid;
  place-items: center;
  margin-bottom: 14px;
  font-size: 20px;
}
.card h3 {
  margin: 0 0 6px;
  font-size: 17px;
}
.card p {
  margin: 0;
  color: var(--muted);
  font-size: 14.5px;
}

/* 隐私卡片标语 */
.privacy-hi {
  border: 1px solid var(--border);
  background: linear-gradient(180deg, var(--accent-soft), transparent);
  border-radius: var(--radius);
  padding: 28px;
  text-align: center;
}
.privacy-hi strong {
  color: var(--accent);
}

/* 文档（隐私政策）排版 */
.doc {
  padding: 48px 0 72px;
}
.doc h1 {
  font-size: 32px;
  letter-spacing: -0.02em;
  margin: 0 0 6px;
}
.doc .updated {
  color: var(--muted);
  font-size: 14px;
  margin: 0 0 32px;
}
.doc h2 {
  font-size: 21px;
  margin: 36px 0 10px;
  padding-top: 8px;
}
.doc h3 {
  font-size: 17px;
  margin: 22px 0 8px;
}
.doc p,
.doc li {
  color: var(--fg);
}
.doc ul {
  padding-left: 22px;
}
.doc li {
  margin: 6px 0;
}
.doc .note {
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  padding: 14px 18px;
  border-radius: 8px;
  margin: 18px 0;
}
.doc table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 14.5px;
}
.doc th,
.doc td {
  border: 1px solid var(--border);
  padding: 10px 12px;
  text-align: left;
  vertical-align: top;
}
.doc th {
  background: var(--surface-2);
  font-weight: 600;
}

/* 页脚 */
footer.site {
  border-top: 1px solid var(--border);
  padding: 32px 0;
  color: var(--muted);
  font-size: 14px;
}
footer.site .container {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: space-between;
  align-items: center;
}
footer.site a {
  color: var(--muted);
}
footer.site a:hover {
  color: var(--fg);
}