:root {
  font-family: Inter, "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: #263850;
  background: #f5f8fc;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  --page: #f5f8fc;
  --surface: #ffffff;
  --text: #263850;
  --muted: #6d7d93;
  --border: #dde6f2;
  --primary: #2563eb;
  --primary-soft: #eaf2ff;
  --green: #168366;
  --green-soft: #e8f7f2;
  --shadow: 0 14px 34px rgba(64, 89, 129, 0.09);
}

* { box-sizing: border-box; }
html { min-width: 320px; scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; background: var(--page); }
a { color: var(--primary); }
a:focus-visible { outline: 3px solid rgba(37, 99, 235, .25); outline-offset: 3px; }
.shell { width: min(920px, calc(100% - 40px)); margin: 0 auto; }

.site-header { border-bottom: 1px solid rgba(221, 230, 242, .9); background: rgba(255, 255, 255, .94); }
.header-inner { width: min(1120px, calc(100% - 40px)); min-height: 70px; margin: 0 auto; display: flex; align-items: center; gap: 20px; }
.brand { color: var(--text); display: inline-flex; align-items: center; gap: 11px; text-decoration: none; }
.brand img { width: 40px; height: 40px; border-radius: 12px; }
.brand span { display: block; }
.brand strong { display: block; font-size: 16px; }
.brand small { display: block; margin-top: 2px; color: var(--muted); font-size: 11px; }
.header-action { margin-left: auto; min-height: 42px; border: 1px solid #c7d8f1; border-radius: 10px; padding: 0 16px; color: var(--primary); background: #fff; display: inline-flex; align-items: center; text-decoration: none; font-size: 14px; font-weight: 700; }

.breadcrumbs { padding-top: 28px; color: #8491a3; font-size: 13px; }
.breadcrumbs a { color: #62728a; text-decoration: none; }
.breadcrumbs span { margin: 0 8px; }
.hero { padding: 44px 0 34px; }
.eyebrow { color: var(--primary); font-size: 12px; font-weight: 750; letter-spacing: .09em; }
.hero h1 { max-width: 820px; margin: 14px 0 16px; color: #20334d; font-size: clamp(34px, 5vw, 52px); line-height: 1.14; letter-spacing: -.035em; }
.hero > p { max-width: 790px; margin: 0; color: #62738a; font-size: 17px; line-height: 1.8; }
.hero-actions { margin-top: 25px; display: flex; flex-wrap: wrap; gap: 10px; }
.primary-link, .secondary-link { min-height: 46px; border-radius: 10px; padding: 0 17px; display: inline-flex; align-items: center; justify-content: center; text-decoration: none; font-size: 14px; font-weight: 700; }
.primary-link { color: #fff; background: linear-gradient(135deg, #2563eb, #2687eb); box-shadow: 0 8px 18px rgba(37, 99, 235, .18); }
.secondary-link { border: 1px solid #d4dfed; color: #405a7b; background: #fff; }

.content-layout { padding-bottom: 84px; display: grid; grid-template-columns: minmax(0, 1fr) 240px; align-items: start; gap: 24px; }
.article { border: 1px solid var(--border); border-radius: 18px; padding: 36px; background: var(--surface); box-shadow: var(--shadow); }
.article section + section { margin-top: 42px; padding-top: 38px; border-top: 1px solid #edf1f6; }
.article h2 { margin: 0 0 15px; color: #273b57; font-size: 25px; letter-spacing: -.02em; }
.article h3 { margin: 24px 0 8px; color: #304762; font-size: 18px; }
.article p, .article li { color: #607086; font-size: 15px; line-height: 1.82; }
.article p { margin: 10px 0; }
.article ol, .article ul { margin: 12px 0 0; padding-left: 24px; }
.article li + li { margin-top: 7px; }
.article strong { color: #334a66; }
.callout { margin: 22px 0; border: 1px solid #cfe0f7; border-radius: 12px; padding: 16px 18px; color: #45627f; background: #f1f6fd; font-size: 14px; line-height: 1.75; }
.callout.green { border-color: #cde9df; color: #39705f; background: #eff9f5; }
.check-grid { margin-top: 18px; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
.check-grid > div { border: 1px solid #e4ebf4; border-radius: 12px; padding: 17px; background: #fbfcfe; }
.check-grid strong { display: block; font-size: 15px; }
.check-grid span { display: block; margin-top: 7px; color: var(--muted); font-size: 13px; line-height: 1.65; }
.comparison { width: 100%; margin-top: 18px; border-collapse: collapse; font-size: 14px; }
.comparison th, .comparison td { border-bottom: 1px solid #e8edf4; padding: 13px 10px; text-align: left; vertical-align: top; line-height: 1.65; }
.comparison th { color: #4d6078; background: #f6f9fd; }
.comparison td { color: #64758b; }
.toc { position: sticky; top: 20px; border: 1px solid var(--border); border-radius: 15px; padding: 20px; background: #fff; }
.toc strong { color: #334963; font-size: 14px; }
.toc a { margin-top: 12px; color: #6e7e93; display: block; text-decoration: none; font-size: 13px; line-height: 1.45; }
.toc a:hover { color: var(--primary); }
.related { margin-top: 22px; }
.related a { border-top: 1px solid #edf1f6; padding: 12px 0; color: #4f6580; display: block; text-decoration: none; font-size: 13px; line-height: 1.45; }
.related a:first-of-type { margin-top: 10px; }

.site-footer { border-top: 1px solid var(--border); padding: 28px 0 40px; color: #7d8b9e; background: #fff; font-size: 12px; line-height: 1.7; }
.footer-inner { width: min(920px, calc(100% - 40px)); margin: 0 auto; display: flex; justify-content: space-between; gap: 20px; }
.footer-inner a { color: #5e7087; text-decoration: none; }

@media (max-width: 760px) {
  .shell, .header-inner, .footer-inner { width: min(100% - 28px, 920px); }
  .brand small { display: none; }
  .header-action { padding: 0 12px; font-size: 13px; }
  .hero { padding-top: 34px; }
  .hero h1 { font-size: 35px; }
  .hero > p { font-size: 15px; }
  .content-layout { grid-template-columns: 1fr; }
  .toc { position: static; grid-row: 1; }
  .article { padding: 24px 20px; }
  .check-grid { grid-template-columns: 1fr; }
  .comparison { display: block; overflow-x: auto; }
  .footer-inner { flex-direction: column; }
}