:root {
  color-scheme: light;
  --ink: #202734;
  --muted: #526176;
  --line: #dce4ee;
  --accent: #1264d8;
  --soft: #f4f7fb;
  font-family: "Segoe UI", "Microsoft YaHei UI", sans-serif;
  color: var(--ink);
  background: #fff;
}
* { box-sizing: border-box; }
html { scroll-padding-top: 24px; }
body { margin: 0; font-size: 16px; line-height: 1.85; }
a { color: var(--accent); text-underline-offset: 4px; }
a:hover { text-decoration-thickness: 2px; }
a:focus-visible, summary:focus-visible { outline: 3px solid #1465df; outline-offset: 5px; }
img { display: block; max-width: 100%; }
h1, h2, h3, p { margin: 0; }
h1, h2, h3 { line-height: 1.45; font-weight: 600; }
h1 { font-size: clamp(28px, 3.6vw, 42px); letter-spacing: -.025em; }
h2 { font-size: 25px; }
h3 { font-size: 21px; }
.skip-link { position: absolute; z-index: 10; top: 8px; left: 12px; padding: 8px 14px; background: #fff; transform: translateY(-160%); }
.skip-link:focus { transform: translateY(0); }
.site-header, .site-footer { width: min(1240px, calc(100% - 80px)); margin: auto; }
.site-header { min-height: 88px; display: flex; justify-content: space-between; align-items: center; gap: 24px; border-bottom: 1px solid var(--line); padding: 16px 0; }
.brand-lockup { display: flex; align-items: center; flex-shrink: 0; gap: 10px; color: var(--ink); text-decoration: none; }
.brand-lockup strong { font-size: 23px; }
.brand-lockup span { font-size: 12px; color: var(--muted); }
.site-nav { display: flex; align-items: center; flex-wrap: wrap; gap: 24px; font-size: 14px; }
.site-nav > a { text-decoration: none; }
.site-nav [aria-current="page"] { color: var(--ink); font-weight: 600; text-decoration: underline; }
.page-shell { width: min(1100px, calc(100% - 80px)); margin: 0 auto; overflow-wrap: anywhere; }
.breadcrumb { margin: 28px 0 36px; font-size: 13px; color: var(--muted); }
.breadcrumb ol { display: flex; flex-wrap: wrap; gap: 6px 10px; list-style: none; padding: 0; margin: 0; }
.breadcrumb li + li::before { content: "/"; margin-right: 10px; color: #778497; }
.breadcrumb a { color: var(--muted); }
.guides-hero { max-width: 800px; margin: 0 0 44px; }
.eyebrow { font-size: 13px; font-weight: 600; color: var(--accent); margin-bottom: 16px; }
.lead { color: var(--muted); font-size: 17px; margin-top: 20px; max-width: 820px; }
.updated { color: var(--muted); font-size: 12px; margin-top: 20px; }
.guides-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 30px; border-top: 1px solid var(--line); }
.guide-card { padding: 27px 0; min-width: 0; display: flex; flex-direction: column; align-items: flex-start; }
.guide-number { color: var(--accent); font-size: 13px; margin-bottom: 16px; }
.guide-card h2 { font-size: 23px; }
.guide-card h2 a, .guide-card h3 a { color: var(--ink); text-decoration: none; }
.guide-card h2 a:hover, .guide-card h3 a:hover { color: var(--accent); text-decoration: underline; }
.guide-card p { font-size: 14px; color: var(--muted); margin: 16px 0 22px; }
.text-link { font-size: 14px; font-weight: 600; margin-top: auto; }
.text-link span { margin-left: 5px; }
.expectation-note { margin: 30px 0 60px; padding: 28px 32px; background: var(--soft); }
.expectation-note h2 { font-size: 21px; margin-bottom: 14px; }
.expectation-note p { font-size: 14px; color: var(--muted); }
.expectation-note p + p { margin-top: 12px; }
.article-hero { max-width: 920px; margin-bottom: 44px; }
.article-layout { display: grid; grid-template-columns: 235px minmax(0, 1fr); gap: 60px; align-items: start; }
.article-toc { position: sticky; top: 24px; font-size: 13px; padding: 20px 0; border-top: 1px solid var(--line); }
.article-toc h2 { font-size: 15px; margin-bottom: 12px; }
.article-toc ol { padding-left: 20px; margin: 0; }
.article-toc li { padding: 5px 0; }
.article-toc a { color: var(--muted); text-decoration: none; }
.article-toc a:hover { color: var(--accent); text-decoration: underline; }
.article-body { min-width: 0; }
.article-section { padding: 20px 0 30px; border-top: 1px solid var(--line); }
.article-section h2 { margin-bottom: 18px; }
.article-section p, .article-section li { color: #415168; }
.article-section p + p { margin-top: 16px; }
.article-section ul, .article-section ol { padding-left: 24px; margin: 20px 0 0; }
.article-section li { padding-left: 4px; margin: 10px 0; }
.steps-list li::marker { color: var(--accent); font-weight: 600; }
.faq-section { padding: 24px 0 0; border-top: 1px solid var(--line); }
.faq-section h2 { margin-bottom: 20px; }
.faq-section details { padding: 18px 0; border-bottom: 1px solid var(--line); }
.faq-section summary { cursor: pointer; font-size: 16px; font-weight: 600; }
.faq-section details p { color: #415168; margin-top: 14px; font-size: 15px; }
.related-guides { margin: 70px 0 32px; padding-top: 32px; border-top: 1px solid var(--line); }
.related-guides > h2 { font-size: 23px; }
.related-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 36px; }
.download-panel { display: flex; justify-content: space-between; align-items: center; gap: 40px; padding: 36px; background: var(--soft); margin: 32px 0 60px; }
.download-panel .eyebrow { margin-bottom: 10px; }
.download-panel h2 { font-size: 24px; }
.download-panel p:not(.eyebrow) { margin-top: 14px; font-size: 14px; color: var(--muted); }
.download-actions { display: flex; flex-direction: column; gap: 12px; flex-shrink: 0; }
.button { display: inline-flex; min-height: 44px; align-items: center; justify-content: center; padding: 10px 20px; border: 1px solid var(--line); border-radius: 5px; font-weight: 600; font-size: 14px; text-decoration: none; line-height: 1.5; text-align: center; }
.button-primary { color: #fff; background: var(--accent); border-color: var(--accent); }
.button-primary:hover { background: #0954be; text-decoration: none; }
.button-secondary { color: var(--ink); background: #fff; }
.button-secondary:hover { border-color: var(--accent); text-decoration: none; }
.nav-download { font-size: 12px; min-height: 36px; padding: 7px 13px; }
.site-footer { border-top: 1px solid var(--line); padding: 30px 0; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 24px; }
.site-footer strong { font-size: 15px; }
.site-footer p { font-size: 12px; color: var(--muted); margin-top: 6px; }
.footer-links { display: flex; flex-wrap: wrap; align-items: center; gap: 14px 24px; font-size: 12px; }
.footer-links a { color: var(--muted); }
@media (max-width: 900px) {
  .site-header, .site-footer, .page-shell { width: calc(100% - 48px); }
  .site-nav { gap: 16px; }
  .guides-grid { grid-template-columns: 1fr; gap: 0; }
  .guides-grid .guide-card { border-bottom: 1px solid var(--line); }
  .article-layout { grid-template-columns: 190px minmax(0, 1fr); gap: 30px; }
  .download-panel { flex-direction: column; align-items: flex-start; }
  .download-actions { flex-direction: row; flex-wrap: wrap; }
}
@media (max-width: 650px) {
  .site-header, .site-footer, .page-shell { width: calc(100% - 32px); }
  .site-header { align-items: flex-start; flex-direction: column; gap: 15px; }
  .site-nav { width: 100%; justify-content: space-between; gap: 8px 12px; font-size: 12px; }
  .nav-download { padding: 7px 9px; font-size: 11px; }
  .breadcrumb { margin: 20px 0 28px; font-size: 12px; }
  .guides-hero, .article-hero { margin-bottom: 28px; }
  .lead { font-size: 16px; }
  .article-layout { grid-template-columns: minmax(0, 1fr); gap: 16px; }
  .article-toc { position: static; padding: 18px 20px; background: var(--soft); }
  .article-toc ol { display: grid; gap: 2px; }
  .article-section h2 { font-size: 23px; }
  .article-section { padding-bottom: 24px; }
  .expectation-note, .download-panel { padding: 24px 20px; }
  .related-guides { margin-top: 44px; }
  .related-grid { grid-template-columns: minmax(0, 1fr); gap: 0; }
  .related-grid .guide-card + .guide-card { border-top: 1px solid var(--line); }
  .download-panel h2 { font-size: 22px; }
  .download-actions { flex-direction: column; width: 100%; }
}