:root {
  --bg: #fbfbfa;
  --surface: #ffffff;
  --text: #1c1d1f;
  --muted: #5d6168;
  --line: #e4e4e1;
  --accent: #2357d8;
  --accent-text: #ffffff;
  --code: #f1f1ee;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #131416;
    --surface: #1b1c1f;
    --text: #ececea;
    --muted: #a3a6ad;
    --line: #2d2f33;
    --accent: #7ea2ff;
    --accent-text: #0d1220;
    --code: #24262a;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

a { color: var(--accent); }

main, .bar, .foot {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 16px;
}

.bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 60px;
  flex-wrap: wrap;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--text);
  font-weight: 650;
  text-decoration: none;
}

.bar nav, .foot nav {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.bar nav { align-items: center; }
.bar nav a:not(.button), .foot nav a { color: var(--muted); text-decoration: none; }
.bar nav a:not(.button):hover, .foot nav a:hover { color: var(--text); }

.hero {
  text-align: center;
  padding: 48px 0 32px;
}

.hero h1 {
  font-size: clamp(2rem, 6vw, 3rem);
  line-height: 1.15;
  max-width: 18em;
  margin: 16px auto 12px;
}

.tagline {
  color: var(--muted);
  font-size: 1.2rem;
  max-width: 34em;
  margin: 0 auto;
}

.actions {
  display: flex;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 24px;
}

.button {
  display: inline-block;
  padding: 10px 20px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: var(--text);
  font-weight: 600;
  text-decoration: none;
}

.button.small { padding: 6px 14px; font-size: 0.9rem; }

.button.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-text);
}

.carousel { position: relative; }

.track {
  display: flex;
  gap: 16px;
  margin: 0;
  padding: 0;
  list-style: none;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scroll-behavior: smooth;
  scrollbar-width: none;
  border-radius: 12px;
}

.track::-webkit-scrollbar { display: none; }
.track > li { flex: 0 0 100%; scroll-snap-align: center; }

@media (prefers-reduced-motion: reduce) {
  .track { scroll-behavior: auto; }
}

.controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-top: 12px;
}

.controls[hidden] { display: none; }

.prev, .next {
  width: 36px;
  height: 36px;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--surface);
  color: var(--text);
  font-size: 1.4rem;
  line-height: 1;
  cursor: pointer;
}

.dots { display: flex; gap: 8px; }

.dots button {
  width: 10px;
  height: 10px;
  padding: 0;
  border: 0;
  border-radius: 50%;
  background: var(--line);
  cursor: pointer;
}

.dots button[aria-current="true"] { background: var(--accent); }

.track img, .doc img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.section { padding: 40px 0 8px; }
.section > h2 { font-size: clamp(1.4rem, 3.5vw, 1.8rem); line-height: 1.25; margin: 0 0 20px; }
.muted { color: var(--muted); }

.badges {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 4px 20px;
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  color: var(--muted);
  font-size: 0.95rem;
}

.badges li::before { content: "✓ "; color: var(--accent); font-weight: 700; }

.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: step;
}

.steps li { counter-increment: step; }

.steps li::before {
  content: counter(step);
  display: inline-grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--accent);
  color: var(--accent-text);
  font-weight: 700;
}

.steps h3, .features h3 { font-size: 1.05rem; margin: 8px 0 4px; }
.steps p, .features p { color: var(--muted); margin: 0; }

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}

.features > div {
  padding: 16px 20px 20px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
}

.providers ul {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  padding: 0;
  margin: 0 0 16px;
}

.providers li {
  padding: 4px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  font-size: 0.95rem;
}

.privacy ul { margin: 0 0 16px; padding-left: 1.2em; }
.privacy li { margin: 6px 0; }

.faq details {
  border-bottom: 1px solid var(--line);
  padding: 12px 0;
}

.faq details:first-of-type { border-top: 1px solid var(--line); }
.faq summary { cursor: pointer; font-weight: 600; }
.faq details p { color: var(--muted); margin: 8px 0 0; }
.faq > p { margin-top: 16px; }

.cta {
  margin: 48px 0;
  padding: 32px 16px;
  border-radius: 16px;
  background: var(--surface);
  border: 1px solid var(--line);
  text-align: center;
}

.cta h2 { margin: 0 0 4px; font-size: clamp(1.4rem, 3.5vw, 1.8rem); }
.cta p { color: var(--muted); margin: 0; }
.cta .actions { margin-top: 20px; }

.hero.compact { padding-bottom: 8px; }
.group .count { color: var(--muted); font-weight: 400; font-size: 0.8em; }
.group > p { margin: -12px 0 16px; }

.service-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.service-list li {
  display: flex;
  flex-direction: column;
  padding: 12px 16px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
}

.service-list span { color: var(--muted); font-size: 0.95rem; }
.note { margin-top: 32px; }

.doc {
  max-width: 760px;
  padding: 16px 0 48px;
  overflow-wrap: anywhere;
}

.doc h1 { line-height: 1.2; }
.doc h2 { margin-top: 2em; padding-top: 0.5em; border-top: 1px solid var(--line); }

.doc code {
  background: var(--code);
  border-radius: 4px;
  padding: 0.1em 0.3em;
  font-size: 0.9em;
}

.doc pre { background: var(--code); padding: 12px; border-radius: 8px; overflow-x: auto; }
.doc pre code { padding: 0; }

.doc table { border-collapse: collapse; display: block; overflow-x: auto; overflow-wrap: normal; }
.doc th, .doc td { min-width: 8em; }
.doc th, .doc td { border: 1px solid var(--line); padding: 6px 10px; text-align: left; vertical-align: top; }

.foot {
  border-top: 1px solid var(--line);
  padding-top: 24px;
  padding-bottom: 40px;
  color: var(--muted);
  font-size: 0.9rem;
}