:root {
  color-scheme: light;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: #f8fafc;
  color: #101828;
  --accent: #2873ed;
  --accent-strong: #175cd3;
  --ink: #101828;
  --body: #344054;
  --muted: #667085;
  --subtle: #98a2b3;
  --line: rgba(15, 23, 42, 0.10);
  --surface: rgba(255, 255, 255, 0.92);
  --soft: #eef4ff;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-height: 100vh; background: linear-gradient(180deg, #f8fbff 0%, #f8fafc 38%, #ffffff 100%); }
img { display: block; max-width: 100%; }
a { color: var(--accent-strong); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  border-bottom: 1px solid var(--line);
  background: rgba(248, 251, 255, 0.9);
  padding: max(12px, env(safe-area-inset-top)) max(20px, calc((100vw - 1040px) / 2)) 12px;
  backdrop-filter: blur(18px);
}
.brand { display: inline-flex; align-items: center; gap: 9px; color: var(--ink); font-weight: 720; }
.brand img { width: 28px; height: 28px; border-radius: 8px; }
.site-header nav { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 6px; }
.site-header nav a { min-height: 36px; border-radius: 999px; padding: 8px 11px; color: #475467; font-size: 13px; font-weight: 650; }
.site-header nav a[aria-current="page"], .site-header nav a:hover { background: #eaf2ff; color: var(--accent-strong); text-decoration: none; }

main { width: min(100%, 1040px); margin: 0 auto; padding: 24px 22px 74px; }
.breadcrumbs { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; color: var(--subtle); font-size: 13px; font-weight: 620; }
.breadcrumbs span:last-child { color: #475467; }
.page { display: grid; gap: 34px; }
.hero { display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(280px, 0.74fr); gap: 38px; align-items: center; padding: 32px 0 18px; }
.hero-copy { min-width: 0; }
.topic { margin: 0 0 14px; color: var(--accent-strong); font-size: 12px; font-weight: 760; letter-spacing: 0; text-transform: uppercase; }
h1 { margin: 0; max-width: 720px; color: var(--ink); font-size: clamp(34px, 5.8vw, 60px); font-weight: 760; letter-spacing: 0; line-height: 1.04; text-wrap: balance; }
.lead { margin: 20px 0 0; max-width: 680px; color: var(--body); font-size: 18px; line-height: 1.76; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 26px; }
.primary-action, .secondary-action {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 0 18px;
  font-size: 15px;
  font-weight: 700;
}
.primary-action { background: var(--accent); color: #fff; box-shadow: 0 12px 28px rgba(40, 115, 237, 0.24); }
.primary-action:hover { background: #175cd3; color: #fff; text-decoration: none; }
.secondary-action { border: 1px solid var(--line); background: var(--surface); color: #475467; }
.secondary-action:hover { background: #fff; text-decoration: none; }
.hero-media { margin: 0; overflow: hidden; border: 1px solid rgba(40, 115, 237, 0.14); border-radius: 8px; background: #fff; box-shadow: 0 24px 60px rgba(16, 24, 40, 0.12); }
.hero-media img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; }

.content-section { border-top: 1px solid var(--line); padding-top: 28px; }
.content-section h2 { margin: 0 0 14px; color: var(--ink); font-size: 22px; line-height: 1.26; letter-spacing: 0; font-weight: 730; }
.content-section p, .content-section li, .content-section td, .content-section th { color: var(--body); font-size: 16px; line-height: 1.82; }
.content-section p { margin: 0; }
.content-section p + p { margin-top: 12px; }
.check-list { display: grid; gap: 8px; margin: 16px 0 0; padding: 0; list-style: none; }
.check-list li { position: relative; padding-left: 24px; }
.check-list li::before { content: ""; position: absolute; left: 0; top: 0.74em; width: 8px; height: 8px; border-radius: 999px; background: var(--accent); }
.example-grid { display: grid; gap: 10px; margin-top: 18px; }
.example-grid div { border: 1px solid var(--line); border-radius: 8px; background: var(--surface); padding: 15px 16px; }
.example-grid strong { display: block; margin-bottom: 5px; color: var(--ink); font-size: 14px; }
.example-grid p { font-size: 15px; line-height: 1.7; }
.table-wrap { overflow-x: auto; margin-top: 16px; border: 1px solid var(--line); border-radius: 8px; background: #fff; }
table { width: 100%; border-collapse: collapse; min-width: 620px; }
th, td { padding: 13px 14px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { color: var(--ink); background: #f3f6fb; font-size: 14px; font-weight: 720; }
tr:last-child td { border-bottom: 0; }
.gallery { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; }
.gallery figure { margin: 0; overflow: hidden; border: 1px solid var(--line); border-radius: 8px; background: #fff; }
.gallery img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; }
.gallery figcaption { padding: 10px 12px; color: #667085; font-size: 13px; font-weight: 600; line-height: 1.5; }
.source-section ul { margin: 12px 0 0; padding-left: 1.2em; }
.faq-list { display: grid; gap: 10px; }
details { border: 1px solid var(--line); border-radius: 8px; background: var(--surface); padding: 14px 16px; }
summary { cursor: pointer; color: var(--ink); font-size: 16px; font-weight: 700; line-height: 1.55; }
details p { margin-top: 9px; font-size: 15px; line-height: 1.72; }
.resource-links { display: grid; gap: 9px; }
.resource-links a { display: grid; gap: 4px; min-height: 58px; border-top: 1px solid var(--line); padding: 12px 2px; }
.resource-links span { color: var(--accent-strong); font-weight: 720; }
.resource-links small { color: var(--muted); font-size: 13px; line-height: 1.55; }
.site-footer { display: flex; flex-wrap: wrap; justify-content: center; gap: 12px; border-top: 1px solid var(--line); padding: 22px; color: var(--muted); font-size: 13px; }

@media (max-width: 820px) {
  .site-header { align-items: flex-start; flex-direction: column; gap: 10px; padding-left: 18px; padding-right: 18px; }
  .site-header nav { justify-content: flex-start; }
  main { padding-left: 20px; padding-right: 20px; }
  .hero { grid-template-columns: 1fr; gap: 24px; padding-top: 24px; }
  .hero-media { order: -1; }
  .lead { font-size: 17px; line-height: 1.7; }
  .gallery { grid-template-columns: 1fr; }
}

@media (max-width: 430px) {
  h1 { font-size: 34px; line-height: 1.08; }
  .content-section h2 { font-size: 20px; }
  .content-section p, .content-section li, .content-section td, .content-section th { font-size: 15.5px; line-height: 1.76; }
}