:root {
  --ink: #1a1a1a;
  --ink-soft: #4a4a4a;
  --muted: #767676;
  --line: #e3e3e3;
  --bg: #ffffff;
  --bg-soft: #f7f7f5;
  --accent: #b3261e;
  --max: 44rem;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 400 17px/1.85 -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-feature-settings: "kern";
  text-rendering: optimizeLegibility;
}

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

a { color: var(--ink); text-decoration-color: #c9c9c9; text-underline-offset: 3px; }
a:hover { color: var(--accent); text-decoration-color: currentColor; }

/* ---------- header / footer ---------- */
.site-header {
  border-bottom: 1px solid var(--line);
  padding: 18px 0;
  margin-bottom: 48px;
}
.site-header .wrap { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.brand { font-weight: 700; font-size: 17px; text-decoration: none; letter-spacing: .01em; }
.site-nav { display: flex; gap: 18px; font-size: 14.5px; }
.site-nav a { text-decoration: none; color: var(--ink-soft); }
.site-nav a:hover { color: var(--accent); }

.site-footer {
  border-top: 1px solid var(--line);
  margin-top: 72px;
  padding: 26px 0 40px;
  font-size: 13.5px;
  color: var(--muted);
}
.site-footer p { margin: 4px 0; }

/* ---------- article head ---------- */
.kicker {
  margin: 0 0 10px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .12em;
  color: var(--accent);
}
.post-head h1 {
  margin: 0 0 16px;
  font-size: 32px;
  line-height: 1.35;
  letter-spacing: -.01em;
}
.lede {
  margin: 0 0 18px;
  font-size: 17px;
  line-height: 1.8;
  color: var(--ink-soft);
}
.post-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin: 0 0 40px;
  padding: 0 0 20px;
  border-bottom: 1px solid var(--line);
  font-size: 13.5px;
  color: var(--muted);
}

/* ---------- toc ---------- */
.toc {
  margin: 0 0 44px;
  padding: 18px 22px;
  background: var(--bg-soft);
  border-left: 3px solid var(--ink);
  font-size: 14.5px;
}
.toc-title { margin: 0 0 8px; font-weight: 700; font-size: 13px; letter-spacing: .08em; color: var(--muted); }
.toc-list { margin: 0; padding-left: 1.2em; }
.toc-list li { margin: 5px 0; }
.toc-list a { text-decoration: none; color: var(--ink-soft); }
.toc-list a:hover { color: var(--accent); }

/* ---------- prose ---------- */
.prose { font-size: 17px; }
.prose > h2 {
  margin: 56px 0 18px;
  padding-top: 8px;
  font-size: 24px;
  line-height: 1.45;
  letter-spacing: -.005em;
  scroll-margin-top: 24px;
}
.prose > h2:first-child { margin-top: 0; }
.prose h3 { margin: 34px 0 12px; font-size: 19px; line-height: 1.5; }
.prose h4 { margin: 26px 0 10px; font-size: 17px; }
.prose p { margin: 0 0 1.1em; }
.prose ul, .prose ol { margin: 0 0 1.2em; padding-left: 1.4em; }
.prose li { margin: .35em 0; }
.prose strong { font-weight: 700; }
.prose hr { border: 0; border-top: 1px solid var(--line); margin: 40px 0; }

.prose blockquote {
  margin: 24px 0;
  padding: 4px 0 4px 20px;
  border-left: 3px solid var(--accent);
  color: var(--ink-soft);
}

/* ---------- tables ---------- */
.prose table {
  width: 100%;
  margin: 26px 0;
  border-collapse: collapse;
  font-size: 14.5px;
  line-height: 1.65;
  display: block;
  overflow-x: auto;
}
.prose caption {
  caption-side: top;
  text-align: left;
  font-size: 13.5px;
  font-weight: 700;
  color: var(--ink-soft);
  padding: 0 0 8px;
}
.prose th, .prose td {
  border: 1px solid var(--line);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}
.prose th { background: var(--bg-soft); font-weight: 700; white-space: nowrap; }
.prose tbody tr:nth-child(even) { background: #fbfbfa; }

/* ---------- faq ---------- */
.faq { margin-top: 12px; }
.faq h3 { margin-top: 26px; }
.faq p { margin-bottom: .6em; }

/* ---------- cite box ---------- */
.cite-box {
  margin: 64px 0 0;
  padding: 22px 24px;
  border: 1px solid var(--line);
  background: var(--bg-soft);
}
.cite-box h2 { margin: 0 0 12px; font-size: 15px; letter-spacing: .06em; }
.cite-text {
  margin: 0 0 10px;
  font-size: 14px;
  line-height: 1.75;
  word-break: break-all;
  color: var(--ink-soft);
}
.cite-meta { margin: 0; font-size: 13px; color: var(--muted); }

/* ---------- author ---------- */
.author-box {
  margin: 32px 0 0;
  padding: 22px 0 0;
  border-top: 1px solid var(--line);
  font-size: 14px;
  color: var(--ink-soft);
}
.author-name { margin: 0 0 6px; font-weight: 700; color: var(--ink); }
.author-bio { margin: 0 0 6px; }
.author-link { margin: 0; color: var(--muted); }

/* ---------- home ---------- */

.cards { list-style: none; margin: 0; padding: 0; }
.card + .card { border-top: 1px solid var(--line); }
.card a { display: block; padding: 22px 0; text-decoration: none; }
.card h2 { margin: 0 0 8px; font-size: 20px; line-height: 1.5; }
.card p { margin: 0; font-size: 15px; color: var(--ink-soft); line-height: 1.7; }
.card-type {
  display: inline-block;
  margin-bottom: 8px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .1em;
  color: var(--accent);
}
.card-meta { display: block; margin-top: 10px; font-size: 13px; color: var(--muted); }

@media (max-width: 600px) {
  body { font-size: 16px; }
  .post-head h1 { font-size: 26px; }
    .prose > h2 { font-size: 21px; }
  .prose table { font-size: 13.5px; }
}

@media print {
  .site-header, .site-nav, .site-footer, .toc, .author-box { display: none; }
  .prose table { display: table; overflow: visible; }
  a { text-decoration: none; color: #000; }
}

/* ---------- summary box ---------- */
.summary {
  margin: 0 0 28px;
  padding: 20px 22px;
  border-left: 3px solid var(--accent);
  background: #fdf7f6;
}
.summary-title {
  margin: 0 0 8px;
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: .12em;
  color: var(--accent);
}
.summary p:last-child { margin: 0; font-size: 16.5px; line-height: 1.75; }

/* 锚点跳转后高亮一下，方便肉眼确认 */
:target { background: #fffbe6; scroll-margin-top: 24px; }

.sources {
  margin: 0 0 28px;
  padding: 16px 20px;
  border: 1px solid var(--line);
  font-size: 14px;
}
.sources-title {
  margin: 0 0 8px;
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: .1em;
  color: var(--muted);
}
.sources ul { margin: 0; padding-left: 1.1em; }
.sources li { margin: 4px 0; }

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- 图片 ---------- */
.prose img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 8px auto;
  border: 1px solid var(--line);
}
.prose figure {
  margin: 30px 0;
  padding: 0;
}
.prose figcaption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
  text-align: center;
}
@media (max-width: 600px) {
  .prose figure { margin: 22px -20px; }
}

.site-footer .icp { margin-top: 10px; font-size: 12.5px; color: var(--muted); }
.site-footer .icp a { color: var(--muted); text-decoration: none; }
.site-footer .icp a:hover { color: var(--ink); }