/* ---------- tokens ---------- */
:root {
  --bg: #fbfaf7;
  --bg-soft: #f2efe9;
  --card: #ffffff;
  --fg: #23201c;
  --fg-soft: #6d675f;
  --fg-faint: #98938b;
  --accent: #8a5a2b;
  --accent-soft: #b98a52;
  --border: #e4dfd6;
  --mark: #f6e7c8;
  --radius: 10px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
  --font-serif: Georgia, "Times New Roman", "Songti SC", "STSong", "Noto Serif CJK SC", "Source Han Serif SC", serif;
  --font-mono: "SFMono-Regular", "JetBrains Mono", Menlo, Consolas, "Liberation Mono", monospace;
}

[data-theme="dark"] {
  --bg: #16171a;
  --bg-soft: #1d1f23;
  --card: #1b1d21;
  --fg: #e7e5e1;
  --fg-soft: #a09b95;
  --fg-faint: #74706a;
  --accent: #dda76c;
  --accent-soft: #c28a4f;
  --border: #2c2f35;
  --mark: #4a3c22;
}

/* ---------- base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  transition: background .25s ease, color .25s ease;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}
main { flex: 1 0 auto; padding: 3rem 1.25rem 4.5rem; }
.wrap { width: 100%; max-width: 44rem; margin: 0 auto; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-soft); text-decoration: underline; text-underline-offset: 3px; }
::selection { background: var(--mark); color: var(--fg); }
.skip { position: absolute; left: -9999px; }
.skip:focus { left: 1rem; top: .5rem; background: var(--card); padding: .5rem .9rem; border-radius: var(--radius); z-index: 99; }

/* ---------- header ---------- */
.site-head {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--bg) 86%, transparent);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--border);
}
.head-inner { display: flex; align-items: center; justify-content: space-between; gap: 1rem; height: 60px; padding: 0 1.25rem; max-width: 56rem; }
.brand { display: inline-flex; align-items: center; gap: .55rem; color: var(--fg); font-weight: 600; letter-spacing: .02em; }
.brand:hover { text-decoration: none; color: var(--accent); }
.brand-mark { width: 15px; height: 15px; border-radius: 4px; background: linear-gradient(135deg, var(--accent), var(--accent-soft)); display: inline-block; }
.brand-text { font-size: 1rem; }
.main-nav { display: flex; align-items: center; gap: 1.15rem; }
.main-nav a { color: var(--fg-soft); font-size: .92rem; }
.main-nav a:hover { color: var(--fg); text-decoration: none; }
.main-nav a.active { color: var(--fg); font-weight: 600; }
#theme-toggle {
  border: 1px solid var(--border); background: var(--card); color: var(--fg-soft);
  width: 32px; height: 32px; border-radius: 8px; cursor: pointer;
  display: inline-flex; align-items: center; justify-content: center;
}
#theme-toggle:hover { color: var(--accent); border-color: var(--accent-soft); }
.i-moon { display: none; }
[data-theme="dark"] .i-sun { display: none; }
[data-theme="dark"] .i-moon { display: inline; }

/* ---------- hero ---------- */
.hero { padding: 1rem 0 2.5rem; border-bottom: 1px solid var(--border); margin-bottom: 2.5rem; }
.hero-title { font-size: 1.9rem; margin: 0 0 .5rem; letter-spacing: .01em; }
.hero-sub { margin: 0; color: var(--fg-soft); font-size: 1rem; }
.hero-desc { margin: .6rem 0 0; color: var(--fg-faint); font-size: .93rem; }
.section-label, .page-title { font-size: 1.35rem; margin: 0 0 1.5rem; }
.page-head { margin-bottom: 2rem; }
.page-desc { color: var(--fg-soft); font-size: .95rem; margin: -.6rem 0 0; }

/* ---------- post list ---------- */
.post-list { list-style: none; margin: 0; padding: 0; }
.post-item + .post-item { border-top: 1px solid var(--border); }
.post-card { padding: 1.35rem 0; }
.post-card-title { margin: 0 0 .4rem; font-size: 1.15rem; line-height: 1.5; font-weight: 600; }
.post-card-title a { color: var(--fg); }
.post-card-title a:hover { color: var(--accent); text-decoration: none; }
.post-card-meta, .post-meta { margin: 0; font-size: .84rem; color: var(--fg-faint); display: flex; flex-wrap: wrap; align-items: center; gap: .35rem; }
.dot { color: var(--border); }
.post-card-summary { margin: .55rem 0 0; color: var(--fg-soft); font-size: .95rem; line-height: 1.75; }
.tag { color: var(--accent); background: color-mix(in srgb, var(--accent) 10%, transparent); padding: .05rem .45rem; border-radius: 5px; font-size: .8rem; }
.tag:hover { text-decoration: none; background: color-mix(in srgb, var(--accent) 20%, transparent); }

/* ---------- pager ---------- */
.pager { display: flex; align-items: center; justify-content: space-between; gap: 1rem; margin-top: 2.5rem; padding-top: 1.25rem; border-top: 1px solid var(--border); font-size: .9rem; }
.pager-btn { color: var(--fg-soft); }
.pager-btn.disabled { color: var(--fg-faint); opacity: .5; }
.pager-num { color: var(--fg-faint); font-size: .84rem; }

/* ---------- tags ---------- */
.tag-cloud { display: flex; flex-wrap: wrap; gap: .6rem; }
.tag-pill {
  display: inline-flex; align-items: center; gap: .45rem;
  padding: .35rem .8rem; border: 1px solid var(--border); border-radius: 999px;
  background: var(--card); color: var(--fg-soft); font-size: .9rem;
}
.tag-pill:hover { border-color: var(--accent-soft); color: var(--accent); text-decoration: none; }
.tag-pill span { font-size: .78rem; color: var(--fg-faint); }

/* ---------- article ---------- */
.post-head { margin-bottom: 1.75rem; }
.post-title { font-size: 1.85rem; line-height: 1.35; margin: 0 0 .7rem; letter-spacing: .01em; }
.toc { margin: 0 0 2rem; padding: .9rem 1.1rem; background: var(--bg-soft); border-radius: var(--radius); font-size: .92rem; }
.toc summary { cursor: pointer; color: var(--fg-soft); font-weight: 600; }
.toc nav > ul { margin: .6rem 0 0; padding-left: 1.1rem; }
.toc ul { list-style: none; padding-left: 1rem; }
.toc li { margin: .2rem 0; }
.toc a { color: var(--fg-soft); }
.toc a:hover { color: var(--accent); }

.post-content { font-family: var(--font-serif); font-size: 1.08rem; line-height: 1.85; color: var(--fg); }
.post-content > *:first-child { margin-top: 0; }
.post-content p { margin: 0 0 1.35em; }
.post-content h2, .post-content h3, .post-content h4 {
  font-family: var(--font-sans); font-weight: 650; line-height: 1.4;
  margin: 2.2em 0 .9em; letter-spacing: .01em; scroll-margin-top: 80px;
}
.post-content h2 { font-size: 1.32rem; padding-bottom: .35rem; border-bottom: 1px solid var(--border); }
.post-content h3 { font-size: 1.12rem; }
.post-content h4 { font-size: 1rem; color: var(--fg-soft); }
.post-content ul, .post-content ol { margin: 0 0 1.35em; padding-left: 1.5em; }
.post-content li { margin: .35em 0; }
.post-content li > ul, .post-content li > ol { margin: .35em 0; }
.post-content blockquote {
  margin: 1.6em 0; padding: .2em 0 .2em 1.1em;
  border-left: 3px solid var(--accent-soft); color: var(--fg-soft); font-style: italic;
}
.post-content blockquote p:last-child { margin-bottom: 0; }
.post-content a { text-decoration: underline; text-decoration-color: color-mix(in srgb, var(--accent) 45%, transparent); text-underline-offset: 3px; }
.post-content strong { font-weight: 650; color: var(--fg); }
.post-content hr { border: 0; border-top: 1px solid var(--border); margin: 2.5em 0; }
.post-content img { max-width: 100%; height: auto; border-radius: var(--radius); display: block; margin: 1.6em auto; }
.post-content figure { margin: 1.6em 0; }
.post-content figcaption { text-align: center; font-size: .85rem; color: var(--fg-faint); font-family: var(--font-sans); margin-top: .5rem; }
.post-content code {
  font-family: var(--font-mono); font-size: .88em; background: var(--bg-soft);
  padding: .15em .4em; border-radius: 4px; border: 1px solid var(--border);
}
.post-content pre {
  background: var(--bg-soft); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1rem 1.1rem; overflow-x: auto; margin: 1.6em 0; line-height: 1.6;
}
.post-content pre code { background: none; border: 0; padding: 0; font-size: .85rem; }
.post-content table { width: 100%; border-collapse: collapse; margin: 1.6em 0; font-family: var(--font-sans); font-size: .95rem; }
.post-content th, .post-content td { border: 1px solid var(--border); padding: .55rem .8rem; text-align: left; }
.post-content th { background: var(--bg-soft); font-weight: 600; }
.post-content .footnotes { font-family: var(--font-sans); font-size: .9rem; color: var(--fg-soft); border-top: 1px solid var(--border); margin-top: 3em; padding-top: 1em; }

/* ---------- post nav ---------- */
.post-nav { display: flex; justify-content: space-between; gap: 1rem; margin-top: 3.5rem; padding-top: 1.5rem; border-top: 1px solid var(--border); }
.post-nav-item { display: flex; flex-direction: column; gap: .2rem; max-width: 48%; color: var(--fg-soft); }
.post-nav-item.right { text-align: right; margin-left: auto; }
.post-nav-item span { font-size: .8rem; color: var(--fg-faint); }
.post-nav-item strong { font-size: .98rem; font-weight: 600; }
.post-nav-item:hover { color: var(--accent); text-decoration: none; }

/* ---------- 404 ---------- */
.notfound { text-align: center; padding: 3rem 0; }
.nf-code { font-size: 3.5rem; margin: 0; color: var(--border); font-weight: 700; letter-spacing: .05em; }
.nf-title { margin: .5rem 0; font-size: 1.3rem; }
.nf-desc { color: var(--fg-soft); margin-bottom: 1.75rem; }
.btn { display: inline-block; padding: .5rem 1.15rem; border: 1px solid var(--border); border-radius: 999px; background: var(--card); font-size: .92rem; }
.btn:hover { border-color: var(--accent-soft); text-decoration: none; }

/* ---------- footer ---------- */
.site-foot { border-top: 1px solid var(--border); background: var(--bg-soft); margin-top: auto; }
.foot-inner { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: .5rem; padding: 1.4rem 1.25rem; max-width: 56rem; font-size: .85rem; color: var(--fg-faint); }
.foot-inner p { margin: 0; }
.foot-right { display: flex; gap: 1rem; }
.foot-right a { color: var(--fg-faint); }
.foot-right a:hover { color: var(--accent); text-decoration: none; }

/* ---------- responsive ---------- */
@media (max-width: 640px) {
  main { padding: 2rem 1.1rem 3.5rem; }
  .hero-title { font-size: 1.6rem; }
  .post-title { font-size: 1.5rem; }
  .post-content { font-size: 1.03rem; }
  .head-inner { height: 54px; }
  .main-nav { gap: .85rem; }
  .post-nav { flex-direction: column; }
  .post-nav-item, .post-nav-item.right { max-width: 100%; text-align: left; }
}
@media print {
  .site-head, .site-foot, .post-nav, #theme-toggle, .toc { display: none !important; }
  body { background: #fff; color: #000; }
}