:root {
  --ink: #16181d;
  --muted: #626871;
  --line: #d9dde3;
  --surface: #ffffff;
  --soft: #f5f6f8;
  --brand: #111827;
  --brand-hover: #374151;
  --accent: #087f5b;
  --warning: #9a6700;
  --danger: #b42318;
  --max-width: 940px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--surface); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; line-height: 1.75; }
a { color: #075f47; text-underline-offset: 3px; }
a:hover { color: #9a6700; }
.site-header { border-bottom: 1px solid var(--line); background: rgba(255,255,255,.97); position: sticky; top: 0; z-index: 10; }
.nav-shell,.footer-shell,.page-shell { width: min(calc(100% - 32px), var(--max-width)); margin: 0 auto; }
.nav-shell { min-height: 64px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); font-weight: 750; text-decoration: none; white-space: nowrap; }
.brand-mark { display: inline-grid; width: 34px; height: 34px; place-items: center; color: #fff; background: var(--brand); border-radius: 6px; font-size: 13px; }
.site-nav { display: flex; align-items: center; gap: 18px; font-size: 15px; }
.site-nav a { color: var(--ink); text-decoration: none; white-space: nowrap; }
.site-nav .nav-cta { color: #fff; background: var(--brand); padding: 8px 12px; border-radius: 6px; }
.site-nav .nav-cta:hover { background: var(--brand-hover); }
.page-shell { padding: 34px 0 72px; }
.content { min-width: 0; }
.content > :first-child { margin-top: 0; }
h1,h2,h3 { line-height: 1.3; letter-spacing: 0; color: #101318; }
h1 { font-size: 2.1rem; margin: 0 0 18px; }
h2 { font-size: 1.5rem; margin: 46px 0 14px; padding-top: 6px; border-top: 1px solid var(--line); }
h3 { font-size: 1.16rem; margin: 28px 0 8px; }
p,ul,ol,table,blockquote { margin: 0 0 20px; }
li + li { margin-top: 7px; }
blockquote { border-left: 4px solid var(--accent); background: var(--soft); padding: 14px 18px; color: #303740; }
table { width: 100%; border-collapse: collapse; display: block; overflow-x: auto; }
th,td { min-width: 140px; border: 1px solid var(--line); padding: 11px 12px; text-align: left; vertical-align: top; }
th { background: var(--soft); }
code { background: #eef0f3; border-radius: 4px; padding: 2px 5px; font-size: .92em; }
img { display: block; max-width: 100%; height: auto; margin: 24px auto; border: 1px solid var(--line); border-radius: 6px; }
.lead { font-size: 1.08rem; color: #343a43; }
.meta { color: var(--muted); font-size: .92rem; }
.notice { border-left: 4px solid var(--warning); padding: 12px 16px; background: #fff9e8; }
.warning { border-left-color: var(--danger); background: #fff5f4; }
.primary-link { display: inline-flex; align-items: center; min-height: 44px; padding: 9px 15px; color: #fff; background: var(--brand); border-radius: 6px; font-weight: 700; text-decoration: none; }
.primary-link:hover { color: #fff; background: var(--brand-hover); }
.guide-grid { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 14px; margin: 24px 0; }
.guide-card { border: 1px solid var(--line); border-radius: 6px; padding: 18px; background: var(--surface); }
.guide-card h3 { margin-top: 0; }
.guide-card p:last-child { margin-bottom: 0; }
.breadcrumbs { display: flex; flex-wrap: wrap; gap: 8px; color: var(--muted); font-size: .9rem; margin-bottom: 22px; }
.breadcrumbs a { color: var(--muted); }
.faq-section details { border-top: 1px solid var(--line); padding: 14px 0; }
.faq-section details:last-child { border-bottom: 1px solid var(--line); }
.faq-section summary { cursor: pointer; font-weight: 700; }
.faq-section details p { margin: 10px 0 0; color: #343a43; }
.site-footer { border-top: 1px solid var(--line); background: var(--soft); }
.footer-shell { padding: 30px 0; color: var(--muted); font-size: .92rem; }
.footer-shell p { margin-bottom: 8px; }
@media (max-width:760px) {
  body { font-size: 16px; }
  .nav-shell { align-items: flex-start; flex-direction: column; padding: 12px 0; gap: 10px; }
  .site-header { position: static; }
  .site-nav { width: 100%; flex-wrap: wrap; gap: 8px 12px; padding-bottom: 2px; }
  h1 { font-size: 1.72rem; }
  h2 { font-size: 1.32rem; }
  .guide-grid { grid-template-columns: 1fr; }
  th,td { min-width: 126px; }
}