:root {
  color-scheme: light;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: #172033;
  background: #fff;
  line-height: 1.8;
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

* { box-sizing: border-box; }

body {
  max-width: 960px;
  min-height: 100vh;
  margin: 0 auto;
  padding: 0 32px;
  display: flex;
  flex-direction: column;
}

.site-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px 24px;
  padding: 28px 0;
  border-bottom: 1px solid #e2e7ef;
  font-size: .875rem;
}

.wordmark { font-weight: 700; letter-spacing: .08em; }
.wordmark span { margin: 0 8px; color: #1d4ed8; }
.site-type, .editor-note, .site-footer { color: #5b6473; }
main { flex: 1; }
.introduction { padding: 64px 0 44px; }
.eyebrow { margin: 0 0 18px; color: #1d4ed8; font-size: .875rem; }
h1 { margin: 0; font-size: clamp(2rem, 6vw, 3.25rem); line-height: 1.3; letter-spacing: -.035em; }
.lead { margin: 22px 0 12px; font-size: 1.25rem; }
.description { max-width: 640px; margin: 0; color: #4b5565; }
.topics { padding-bottom: 44px; }
h2 { margin: 0 0 14px; font-size: .875rem; color: #5b6473; font-weight: 500; }
.topic {
  display: grid;
  grid-template-columns: 40px 140px 1fr;
  gap: 16px;
  align-items: baseline;
  padding: 20px 0;
  border-top: 1px solid #e2e7ef;
}
.topic-number { color: #1d4ed8; font-size: .875rem; font-variant-numeric: tabular-nums; }
h3 { margin: 0; font-size: 1rem; font-weight: 600; }
.topic p { margin: 0; color: #4b5565; }
.editor-note { margin: 16px 0 0; font-size: .875rem; }
.site-footer { padding: 24px 0 28px; border-top: 1px solid #e2e7ef; text-align: center; font-size: .875rem; }
.site-footer p { margin: 0 0 4px; }
a { color: inherit; text-decoration-thickness: 1px; text-underline-offset: 4px; }
a:hover { color: #1d4ed8; }
a:focus-visible { outline: 2px solid #1d4ed8; outline-offset: 5px; border-radius: 2px; }

@media (max-width: 600px) {
  body { padding: 0 22px; }
  .site-header { padding: 20px 0; }
  .introduction { padding: 42px 0 32px; }
  .topic { grid-template-columns: 28px 1fr; gap: 4px 12px; padding: 18px 0; }
  .topic p { grid-column: 2; }
}