:root {
  --seo-bg: #f4f7fb;
  --seo-surface: #ffffff;
  --seo-ink: #172033;
  --seo-muted: #596579;
  --seo-line: #dbe3ed;
  --seo-accent: #0a73e8;
  --seo-accent-dark: #0759b3;
  --seo-soft: #eaf3ff;
  --seo-warn: #7a5a14;
  --seo-warn-bg: #fff8e7;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body.seo-page {
  margin: 0;
  background: var(--seo-bg);
  color: var(--seo-ink);
  font-family: "Noto Sans SC", "Microsoft YaHei", system-ui, sans-serif;
  line-height: 1.75;
  overflow-x: hidden;
}

.seo-skip {
  position: absolute;
  left: 1rem;
  top: -4rem;
  z-index: 10;
  padding: .5rem .75rem;
  background: var(--seo-ink);
  color: white;
}
.seo-skip:focus { top: 1rem; }

.seo-header {
  background: rgba(255, 255, 255, .96);
  border-bottom: 1px solid var(--seo-line);
}

.seo-header-inner,
.seo-main,
.seo-footer-inner {
  width: min(1120px, calc(100% - 2rem));
  margin: 0 auto;
}

.seo-header-inner {
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.seo-brand {
  display: inline-flex;
  align-items: center;
  gap: .65rem;
  color: var(--seo-ink);
  text-decoration: none;
  font-weight: 760;
}
.seo-brand img { width: 34px; height: 34px; }
.seo-brand span { color: var(--seo-muted); font-size: .82rem; font-weight: 500; }

.seo-nav { display: flex; flex-wrap: wrap; gap: .35rem 1rem; }
.seo-nav a,
.seo-footer a,
.seo-related a { color: var(--seo-accent-dark); }
.seo-nav a { color: var(--seo-muted); text-decoration: none; font-size: .9rem; }
.seo-nav a:hover, .seo-nav a:focus-visible { color: var(--seo-accent-dark); }

.seo-main { padding: 3.5rem 0 4.5rem; }

.seo-hero {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(260px, .55fr);
  gap: 2rem;
  align-items: start;
  padding-bottom: 3rem;
}

.seo-eyebrow {
  margin: 0 0 .65rem;
  color: var(--seo-accent-dark);
  font-size: .82rem;
  font-weight: 760;
  letter-spacing: .08em;
}

.seo-hero h1 {
  max-width: 16ch;
  margin: 0;
  font-size: clamp(2.25rem, 6vw, 4.5rem);
  line-height: 1.08;
  letter-spacing: -.045em;
}

.seo-lead {
  max-width: 46rem;
  margin: 1.2rem 0 1.5rem;
  color: var(--seo-muted);
  font-size: clamp(1.05rem, 2vw, 1.25rem);
}

.seo-actions { display: flex; flex-wrap: wrap; gap: .75rem; }
.seo-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: .65rem 1rem;
  border: 1px solid var(--seo-accent);
  border-radius: 8px;
  background: var(--seo-accent);
  color: white;
  font-weight: 700;
  text-decoration: none;
}
.seo-button:hover, .seo-button:focus-visible { background: var(--seo-accent-dark); }
.seo-button.secondary { background: white; color: var(--seo-accent-dark); }

.seo-fact {
  padding: 1.25rem;
  border: 1px solid var(--seo-line);
  border-radius: 12px;
  background: var(--seo-surface);
}
.seo-fact strong { display: block; margin-bottom: .35rem; }
.seo-fact p { margin: 0; color: var(--seo-muted); font-size: .92rem; }

.seo-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-bottom: 1rem;
}

.seo-section {
  padding: 1.5rem;
  border: 1px solid var(--seo-line);
  border-radius: 12px;
  background: var(--seo-surface);
}
.seo-section.wide { margin: 1rem 0; }
.seo-section h2 { margin: 0 0 .75rem; font-size: 1.35rem; line-height: 1.3; }
.seo-section h3 { margin: 1rem 0 .35rem; font-size: 1rem; }
.seo-section p { margin: .55rem 0; }
.seo-section ul, .seo-section ol { margin: .5rem 0 0; padding-left: 1.25rem; }
.seo-section li + li { margin-top: .35rem; }

.seo-limit {
  border-color: #ecd99a;
  background: var(--seo-warn-bg);
  color: var(--seo-warn);
}

.seo-faq details { border-top: 1px solid var(--seo-line); padding: .85rem 0; }
.seo-faq details:first-of-type { border-top: 0; }
.seo-faq summary { cursor: pointer; font-weight: 700; }
.seo-faq p { color: var(--seo-muted); }

.seo-related ul {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: .75rem;
  padding: 0;
  list-style: none;
}
.seo-related a {
  display: block;
  min-height: 100%;
  padding: .85rem;
  border: 1px solid var(--seo-line);
  border-radius: 8px;
  background: white;
  text-decoration: none;
  font-weight: 650;
}

.seo-footer { border-top: 1px solid var(--seo-line); background: white; }
.seo-footer-inner { padding: 1.5rem 0; color: var(--seo-muted); font-size: .88rem; }
.seo-footer-inner p { margin: .35rem 0; }

@media (max-width: 760px) {
  .seo-header-inner { align-items: flex-start; flex-direction: column; padding: .85rem 0; }
  .seo-nav { width: 100%; }
  .seo-main { padding-top: 2.25rem; }
  .seo-hero, .seo-grid { grid-template-columns: 1fr; }
  .seo-hero { gap: 1.25rem; }
  .seo-related ul { grid-template-columns: 1fr; }
}

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