:root {
  --front-shell-width: 1180px;
  --gutter: 32px;
  --ink: #19232f;
  --muted: #5b6675;
  --accent: #2254ce;
  --accent-hover: #183fa2;
  --line: #dce2ea;
  --surface: #f7f9fc;
  --radius: 8px;
  --canvas: #ffffff;
  --border: #cfd8e5;
  --prose: #455163;
  --strong: #344255;
  --button-bg: #2254ce;
  --button-hover: #183fa2;
  color-scheme: light;
}
:root[data-theme="dark"] {
  --ink: #e6eaf1;
  --muted: #b4becd;
  --accent: #93b4ff;
  --accent-hover: #b4cbff;
  --line: #3b4553;
  --surface: #1c2128;
  --canvas: #14171c;
  --border: #4b586c;
  --prose: #c5cedb;
  --strong: #d2dbea;
  --button-bg: #315ccd;
  --button-hover: #3d6bd9;
  color-scheme: dark;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 28px; }
body { margin: 0; color: var(--ink); background: var(--canvas); font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif; font-size: 16px; line-height: 1.75; -webkit-font-smoothing: antialiased; }
a { color: inherit; text-decoration: none; }
a:hover { color: var(--accent); }
a:focus-visible, button:focus-visible, summary:focus-visible { outline: 3px solid var(--accent); outline-offset: 5px; border-radius: 2px; }
img { max-width: 100%; vertical-align: middle; }
h1, h2, h3, p, dl { margin: 0; }
h1, h2, h3 { line-height: 1.35; }
.shell { width: min(var(--front-shell-width), calc(100% - var(--gutter) * 2)); margin-inline: auto; }
.skip { position: absolute; top: -80px; left: 16px; z-index: 5; padding: 12px; background: var(--canvas); }
.skip:focus { top: 8px; }
.header { min-height: 82px; display: flex; justify-content: space-between; align-items: center; gap: 24px; border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; align-items: center; gap: 10px; white-space: nowrap; font-size: 21px; font-weight: 700; letter-spacing: -.4px; }
.header-actions { display: flex; align-items: center; gap: 25px; }
.theme-toggle { display: inline-flex; justify-content: center; align-items: center; min-width: 48px; height: 34px; padding: 0 10px; border: 1px solid var(--border); border-radius: 5px; background: var(--canvas); color: var(--ink); font: inherit; font-size: 13px; cursor: pointer; }
.theme-toggle:hover { background: var(--surface); border-color: var(--muted); }
.theme-toggle[hidden] { display: none; }
.header nav { display: flex; gap: 32px; align-items: center; }
.header nav a { font-size: 15px; color: var(--muted); padding: 28px 0 25px; border-bottom: 2px solid transparent; }
.header nav a[aria-current] { color: var(--ink); border-color: var(--accent); font-weight: 600; }
.header nav a:hover { color: var(--accent); }
.kicker { color: var(--accent); font-size: 14px; font-weight: 600; letter-spacing: .4px; margin-bottom: 12px; }
.intro { display: grid; grid-template-columns: minmax(0, 1fr) 265px; gap: 64px; padding-block: 48px 42px; align-items: center; }
.intro h1 { font-size: clamp(32px, 3.3vw, 44px); letter-spacing: -1.5px; font-weight: 700; margin-bottom: 18px; }
.mobile-break { display: none; }
.intro-text { color: var(--muted); font-size: 17px; line-height: 1.9; }
.editor-note { border-left: 1px solid var(--line); padding-left: 28px; }
.editor-note > span { color: var(--muted); font-size: 13px; }
.editor-note p { margin: 10px 0 15px; font-size: 15px; line-height: 1.9; }
.editor-note a { color: var(--accent); font-size: 14px; font-weight: 600; }
.editor-note a span { margin-left: 12px; }
.section-heading { display: flex; justify-content: space-between; align-items: end; gap: 24px; margin-bottom: 22px; }
.section-heading h2 { font-size: 24px; font-weight: 650; letter-spacing: -.4px; }
.section-heading > p { color: var(--muted); font-size: 14px; padding-bottom: 2px; }
.recommendations { padding-block: 0 40px; }
.service-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
.service { padding: 25px 28px 26px; border: 1px solid var(--border); border-radius: var(--radius); background: var(--canvas); display: flex; flex-direction: column; }
.service-heading { display: flex; justify-content: space-between; align-items: center; margin-bottom: 13px; }
.service-category { font-size: 13px; color: var(--accent); font-weight: 600; }
.service-index { color: var(--muted); font-size: 13px; font-variant-numeric: tabular-nums; }
.service h3 { font-size: 32px; letter-spacing: -.7px; margin-bottom: 12px; font-weight: 650; }
.local-name { font-size: 20px; font-weight: 500; color: var(--muted); margin-left: 12px; }
.service-description { font-size: 16px; color: var(--muted); line-height: 1.85; margin-bottom: 22px; flex: 1; }
.service-meta { border-top: 1px solid var(--line); padding-top: 14px; margin-bottom: 22px; }
.service-meta > div { display: flex; gap: 20px; align-items: baseline; padding-block: 4px; font-size: 14px; }
.service-meta dt { min-width: 62px; color: var(--muted); }
.service-meta dd { margin: 0; }
.service-meta a { color: var(--accent); }
.service-actions { display: flex; gap: 20px; justify-content: space-between; align-items: center; }
.button { display: inline-flex; justify-content: center; align-items: center; gap: 26px; background: var(--button-bg); border: 1px solid var(--button-bg); border-radius: 5px; padding: 10px 17px; font-weight: 600; font-size: 15px; line-height: 1.8; transition: background .15s; }
.button, .button:hover { color: #fff; }
.button:hover { background: var(--button-hover); border-color: var(--button-hover); }
.detail-link, .text-link { font-size: 15px; font-weight: 500; white-space: nowrap; }
.detail-link span { margin-left: 8px; }
.affiliate-note { margin-top: 14px; font-size: 13px; color: var(--muted); }
.affiliate-note a { text-decoration: underline; text-underline-offset: 3px; margin-left: 5px; }
.selection-section { background: var(--surface); border-block: 1px solid var(--line); padding-block: 40px; }
.selection-section .section-heading { margin-bottom: 26px; }
.selection-section .kicker, .faq-section .kicker { margin-bottom: 5px; }
.selection-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 32px; }
.selection-grid article + article { border-left: 1px solid var(--line); padding-left: 32px; }
.step-number { display: inline-block; color: var(--accent); font-size: 13px; font-weight: 600; margin-bottom: 11px; font-variant-numeric: tabular-nums; }
.selection-grid h3 { font-size: 18px; margin-bottom: 10px; }
.selection-grid p { font-size: 15px; color: var(--muted); line-height: 1.85; }
.faq-section { padding-block: 44px 54px; }
.faq-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 44px; }
details { border-bottom: 1px solid var(--line); padding-block: 18px; }
summary { position: relative; padding-right: 25px; font-size: 16px; font-weight: 600; cursor: pointer; list-style: none; }
summary::-webkit-details-marker { display: none; }
summary::after { content: '+'; position: absolute; right: 3px; color: var(--muted); font-size: 21px; line-height: 1.3; font-weight: 400; }
details[open] summary::after { content: '−'; }
details p { font-size: 15px; color: var(--muted); line-height: 1.85; margin-top: 13px; }
details a { color: var(--accent); text-decoration: underline; text-underline-offset: 3px; }
.site-footer { border-top: 1px solid var(--line); background: var(--surface); }
.footer-top { display: flex; justify-content: space-between; align-items: center; gap: 30px; padding-block: 28px 24px; }
.footer-top .brand { font-size: 18px; }
.footer-top p { color: var(--muted); font-size: 13px; margin-top: 6px; }
.footer-links { display: flex; gap: 27px; font-size: 14px; color: var(--muted); }
.footer-note { border-top: 1px solid var(--line); padding-block: 20px 28px; }
.footer-note p { color: var(--muted); font-size: 13px; line-height: 1.9; max-width: 1050px; }
.footer-note p + p { margin-top: 7px; }
.footer-note strong { font-weight: 600; color: var(--strong); margin-right: 8px; }
.footer-note span { display: inline-block; margin-left: 16px; }
.article-page { padding-block: 28px 64px; }
.back { color: var(--muted); font-size: 14px; display: inline-block; margin-bottom: 32px; }
.article-header { border-bottom: 1px solid var(--line); padding-bottom: 30px; margin-bottom: 35px; }
.article-header h1 { font-size: 42px; font-weight: 700; letter-spacing: -1px; margin-bottom: 14px; }
.article-header h1 span { font-size: 29px; color: var(--muted); font-weight: 500; margin-left: 8px; }
.article-deck { max-width: 730px; color: var(--muted); font-size: 17px; line-height: 1.85; }
.article-meta { margin-top: 18px; font-size: 13px; color: var(--muted); }
.article-meta span { margin-left: 20px; }
.article-grid { display: grid; grid-template-columns: minmax(0, 740px) minmax(230px, 1fr); gap: 76px; align-items: start; }
.prose { font-size: 17px; line-height: 1.95; }
.prose section + section { margin-top: 34px; }
.prose h3 { font-size: 19px; margin: 23px 0 10px; font-weight: 600; }
.prose h2 { font-size: 24px; margin-bottom: 16px; font-weight: 650; }
.prose p { color: var(--prose); margin-bottom: 16px; }
.prose a { color: var(--accent); text-decoration: underline; text-underline-offset: 4px; }
.prose ul { padding-left: 23px; margin: 0 0 20px; color: var(--prose); }
.prose ul li { margin-bottom: 10px; }
.prose strong { color: var(--ink); font-weight: 600; }
.article-aside { position: sticky; top: 24px; }
.aside-action { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; }
.aside-action h2 { font-size: 21px; margin-bottom: 10px; }
.aside-action > p:not(.kicker) { color: var(--muted); font-size: 15px; margin-bottom: 20px; }
.aside-action .button { width: 100%; gap: 14px; padding-inline: 10px; white-space: nowrap; }
.aside-action small { display: block; font-size: 12px; color: var(--muted); margin-top: 12px; text-align: center; }
.toc { margin-top: 25px; border-left: 1px solid var(--line); padding-left: 20px; display: flex; flex-direction: column; align-items: start; gap: 10px; }
.toc p { font-size: 13px; color: var(--muted); margin-bottom: 3px; }
.toc a { font-size: 14px; }
.guide-page .toc { margin-top: 0; }
.article-steps { list-style: decimal-leading-zero; margin: 0 0 22px; padding-left: 29px; }
.article-steps li { padding-left: 7px; margin-bottom: 16px; }
.article-steps li::marker { color: var(--accent); font-size: 14px; }
.article-steps p { margin: 3px 0 0; font-size: 16px; }
.source-note { border-top: 1px solid var(--line); margin-top: 34px; padding-top: 18px; font-size: 14px; color: var(--muted); }
.document-link { display: flex; align-items: center; justify-content: space-between; gap: 16px; border: 1px solid var(--line); border-radius: 5px; padding: 18px 20px; margin-block: 20px; font-size: 16px; }
.document-link p { margin: 2px 0 0; font-size: 14px; color: var(--muted); }
.document-link > a { font-size: 14px; white-space: nowrap; text-decoration: none; }
.glossary > div { padding: 16px 0; border-bottom: 1px solid var(--line); display: grid; grid-template-columns: 95px 1fr; gap: 20px; }
.glossary > div:first-child { padding-top: 0; }
.glossary dt { font-weight: 600; }
.glossary dd { margin: 0; color: var(--prose); }
.section-number { color: var(--accent); font-size: 17px; margin-right: 13px; font-variant-numeric: tabular-nums; }
.next-reading { display: flex; gap: 25px; flex-wrap: wrap; border-top: 1px solid var(--line); margin-top: 32px; padding-top: 22px; font-size: 15px; }
.next-reading > span { color: var(--muted); }
@media (max-width: 1000px) {
  .intro { gap: 35px; grid-template-columns: minmax(0, 1fr) 230px; }
  .intro h1 { font-size: 36px; }
  .desktop-break { display: none; }
  .service { padding-inline: 24px; }
  .service h3 { font-size: 29px; }
  .service-actions { gap: 12px; }
  .button { gap: 13px; padding-inline: 14px; }
  .article-grid { gap: 40px; grid-template-columns: minmax(0, 1fr) 260px; }
}
@media (max-width: 700px) {
  :root { --gutter: 16px; }
  .header { min-height: 70px; gap: 16px; }
  .brand { font-size: 19px; gap: 8px; }
  .header .brand img { width: 28px; height: 28px; }
  .header-actions { gap: 14px; }
  .header nav { gap: 14px; }
  .header nav a { font-size: 14px; padding-block: 23px 20px; }
  .header .about-link { display: none; }
  .intro { grid-template-columns: 1fr; padding-block: 31px 28px; gap: 0; }
  .intro h1 { font-size: 33px; letter-spacing: -.8px; margin-bottom: 14px; }
  .mobile-break { display: initial; }
  .intro-text { font-size: 16px; line-height: 1.85; }
  .intro .kicker { font-size: 13px; margin-bottom: 10px; }
  .editor-note { display: none; }
  .section-heading { margin-bottom: 17px; gap: 12px; }
  .section-heading h2 { font-size: 21px; }
  .recommendations .section-heading > p { font-size: 12px; }
  .service-grid { grid-template-columns: 1fr; gap: 18px; }
  .service { padding: 21px 22px 22px; }
  .service-heading { margin-bottom: 11px; }
  .service h3 { font-size: 30px; margin-bottom: 11px; }
  .service-description { font-size: 16px; margin-bottom: 19px; }
  .service-meta { padding-top: 12px; margin-bottom: 20px; }
  .service-meta > div { gap: 18px; font-size: 14px; padding-block: 4px; }
  .button { padding: 10px 14px; gap: 17px; font-size: 14px; }
  .detail-link { font-size: 14px; }
  .detail-link span { margin-left: 3px; }
  .affiliate-note { font-size: 13px; line-height: 1.8; }
  .affiliate-note a { margin-left: 0; }
  .recommendations { padding-bottom: 29px; }
  .selection-section { padding-block: 29px; }
  .selection-section .section-heading { margin-bottom: 21px; }
  .selection-section .text-link { font-size: 13px; }
  .selection-grid { grid-template-columns: 1fr; gap: 20px; }
  .selection-grid article { position: relative; padding-left: 37px; }
  .selection-grid article + article { border-left: 0; border-top: 1px solid var(--line); padding: 20px 0 0 37px; }
  .step-number { position: absolute; left: 0; top: 1px; }
  .selection-grid article + article .step-number { top: 21px; }
  .selection-grid h3 { font-size: 17px; margin-bottom: 7px; }
  .selection-grid p { font-size: 15px; }
  .faq-section { padding-block: 31px 36px; }
  .faq-section .section-heading { display: block; margin-bottom: 8px; }
  .faq-section .section-heading > p { font-size: 14px; margin-top: 8px; }
  .faq-list { grid-template-columns: 1fr; gap: 0; }
  summary { font-size: 16px; }
  details { padding-block: 17px; }
  .footer-top { flex-direction: column; align-items: start; padding-block: 24px 20px; gap: 17px; }
  .footer-top .brand { font-size: 18px; }
  .footer-links { flex-wrap: wrap; gap: 23px; }
  .footer-note { padding-block: 17px 24px; }
  .footer-note span { margin-left: 0; display: block; margin-top: 5px; }
  .article-page { padding-block: 23px 38px; }
  .back { margin-bottom: 24px; }
  .article-header { padding-bottom: 23px; margin-bottom: 24px; }
  .article-header h1 { font-size: 33px; letter-spacing: -.7px; }
  .article-header h1 span { font-size: 22px; margin-left: 6px; }
  .article-deck { font-size: 16px; }
  .article-meta { margin-top: 14px; }
  .article-grid { grid-template-columns: 1fr; gap: 28px; }
  .article-aside { position: static; order: -1; }
  .aside-action { padding: 19px 20px; }
  .aside-action .kicker { margin-bottom: 6px; }
  .aside-action h2 { font-size: 21px; }
  .aside-action > p:not(.kicker) { font-size: 14px; margin-bottom: 15px; }
  .aside-action .button { width: auto; min-width: 185px; }
  .aside-action small { display: inline-block; text-align: left; margin-top: 9px; }
  .toc { display: none; }
  .guide-page .toc { display: flex; flex-direction: row; flex-wrap: wrap; gap: 8px 16px; padding-left: 0; border: 0; padding-bottom: 19px; border-bottom: 1px solid var(--line); }
  .guide-page .toc p { flex-basis: 100%; margin-bottom: 2px; }
  .guide-page .toc a { font-size: 14px; }
  .prose { font-size: 16.5px; line-height: 1.95; }
  .prose h2 { font-size: 22px; margin-bottom: 14px; }
  .prose section + section { margin-top: 29px; }
  .document-link { padding: 16px; flex-direction: column; align-items: start; gap: 8px; }
  .glossary > div { grid-template-columns: 1fr; gap: 4px; }
  .article-steps p { font-size: 16px; }
  .next-reading { gap: 12px 23px; }
  .next-reading > span { flex-basis: 100%; }
}
@media (max-width: 380px) {
  .header { gap: 10px; }
  .header-actions { gap: 10px; }
  .header .brand { font-size: 17px; gap: 6px; }
  .header .brand img { width: 24px; height: 24px; }
  .header nav { gap: 12px; }
  .header nav a { font-size: 13px; }
  .theme-toggle { min-width: 40px; padding-inline: 6px; font-size: 12px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; }
}