:root {
  color-scheme: light dark;
  --background: #fbfbfd;
  --text: #1d1d1f;
  --secondary: #6e6e73;
  --line: #e5e5e7;
  --link: #0066cc;
  --surface: #f3f3f5;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Segoe UI", "Microsoft YaHei", Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --background: #080808;
    --text: #f5f5f7;
    --secondary: #a1a1a6;
    --line: #303033;
    --link: #2997ff;
    --surface: #1c1c1e;
  }
}

* { box-sizing: border-box; }
body {
  margin: 0;
  min-width: 320px;
  padding: 0 clamp(24px, 6vw, 64px);
  background: var(--background);
  color: var(--text);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.55;
  font-optical-sizing: auto;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--link); text-decoration: none; }
button { font: inherit; color: inherit; }
img { max-width: 100%; height: auto; }
iframe { max-width: 100%; }

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  min-height: 82px;
  max-width: 960px;
  margin: 0 auto;
  border-bottom: 1px solid var(--line);
}
.is-home .site-header { border-bottom: 0; }
.home-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--text);
  font-size: 19px;
  font-weight: 500;
  line-height: 1.2;
  letter-spacing: -0.035em;
}
.section-nav { display: flex; align-items: center; gap: 27px; }
.section-nav a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--secondary);
  font-size: 12px;
  letter-spacing: -0.01em;
}
.section-nav a[aria-current="page"] { color: var(--text); font-weight: 500; }
.home-link:hover,
.home-link:focus-visible,
.section-nav a:hover,
.section-nav a:focus-visible { color: var(--link); }

.section-page { max-width: 740px; margin: 0 auto; padding: 58px 0 100px; }
h1 {
  margin: 0;
  font-size: clamp(38px, 5vw, 54px);
  font-weight: 500;
  line-height: 1.1;
  letter-spacing: -0.045em;
  overflow-wrap: anywhere;
}
.section-page > h1 { margin-bottom: 43px; }
.page-content > :first-child { margin-top: 0; }
.empty-state { margin: 0; padding: 30px 0 90px; color: var(--secondary); }

.entry-list { padding: 0; margin: 0; list-style: none; border-top: 1px solid var(--line); }
.entry-list > li { border-bottom: 1px solid var(--line); }
.entry-link { display: flex; align-items: center; justify-content: space-between; gap: 24px; padding: 25px 0; color: var(--text); }
.entry-title { display: block; font-size: 21px; font-weight: 500; line-height: 1.3; letter-spacing: -0.025em; }
.entry-detail { display: block; margin-top: 6px; color: var(--secondary); font-size: 14px; line-height: 1.5; }
.entry-chevron { flex-shrink: 0; color: var(--secondary); }
.entry-link:hover,
.entry-link:focus-visible { color: var(--link); }

.reading-page { max-width: 660px; margin: 0 auto; padding: 25px 0 100px; }
.back-link { display: inline-flex; align-items: center; min-height: 44px; margin-bottom: 28px; font-size: 14px; }
.article-meta { margin: 17px 0 44px; color: var(--secondary); font-size: 14px; }
.reading-content { font-size: 18px; line-height: 1.85; letter-spacing: -0.012em; overflow-wrap: anywhere; }
.reading-content p { margin: 0 0 24px; }
.reading-content h2 { margin: 38px 0 17px; font-size: 26px; font-weight: 500; line-height: 1.3; letter-spacing: -0.03em; }
.reading-content ul,
.reading-content ol { padding-left: 23px; }
.reading-content li { padding-left: 3px; margin-bottom: 8px; }
.reading-content hr { margin: 36px 0; border: 0; border-top: 1px solid var(--line); }
.reading-content pre { padding: 18px; overflow-x: auto; background: var(--surface); border-radius: 8px; }
code { font-family: ui-monospace, "SFMono-Regular", Menlo, monospace; font-size: 0.9em; }
.reading-content blockquote { margin: 24px 0; padding-left: 20px; border-left: 2px solid var(--line); color: var(--secondary); }
.reading-content table { display: block; max-width: 100%; overflow-x: auto; border-collapse: collapse; }
.reading-content th,
.reading-content td { padding: 10px; border-bottom: 1px solid var(--line); text-align: left; }
.post-navigation {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  margin-top: 52px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}
.post-navigation a { min-width: 0; overflow-wrap: anywhere; }
.post-direction { display: block; margin-bottom: 8px; color: var(--secondary); font-size: 13px; }
.post-next { grid-column: 2; text-align: right; }
:lang(zh) { letter-spacing: normal; }
.reading-content:lang(zh) { line-height: 1.95; }

.visually-hidden,
.skip-link:not(:focus) { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }
.skip-link:focus { position: absolute; z-index: 10; top: 8px; left: 24px; padding: 8px 12px; background: var(--background); }

@media (max-width: 680px) {
  .site-header { min-height: 73px; }
  .section-nav { gap: 18px; }
  .section-page { padding: 43px 0 75px; }
  .entry-title { font-size: 19px; }
  .entry-detail { font-size: 13px; }
  .reading-content { font-size: 17px; }
}
@media (max-width: 420px) {
  body:not(.is-home) .site-header { display: block; padding: 10px 0 0; }
  .section-nav { justify-content: space-between; gap: 12px; }
  .entry-link { gap: 15px; }
  .article-meta { margin-bottom: 30px; }
  .post-navigation { grid-template-columns: 1fr; }
  .post-next { grid-column: 1; text-align: left; }
}