:root {
  --bg: #fffefb;
  --fg: #1f2328;
  --muted: #6b7280;
  --rule: #e6e3dd;
  --link: #1a5fb4;
  --chip-bg: #f2f0eb;
  --chip-fg: #4b5563;
  --code-bg: #f5f3ee;
  --quote-bar: #d8d4cc;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue",
    "PingFang TC", "Noto Sans TC", "Microsoft JhengHei", "Hiragino Sans", sans-serif;
  --leading: 1.85;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
    "PingFang TC", "Noto Sans TC", monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a;
    --fg: #e4e2dd;
    --muted: #9aa1ab;
    --rule: #2b2f36;
    --link: #7fb0f2;
    --chip-bg: #22262c;
    --chip-fg: #b6bcc5;
    --code-bg: #1c2026;
    --quote-bar: #3a3f47;
  }
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font);
  font-size: 18px;
  line-height: var(--leading);
  overflow-wrap: break-word;
}

main,
header.site,
footer.site {
  max-width: 680px;
  margin: 0 auto;
  padding: 0 24px;
}

header.site {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 20px;
  padding-top: 56px;
  padding-bottom: 40px;
}

header.site nav a { color: var(--muted); font-size: 0.85rem; }
header.site nav a:hover { color: var(--link); text-decoration: none; }

.brand {
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--fg);
  text-decoration: none;
}

.brand:hover { color: var(--link); }

footer.site {
  margin-top: 88px;
  padding-top: 24px;
  padding-bottom: 64px;
  border-top: 1px solid var(--rule);
  color: var(--muted);
  font-size: 0.85rem;
}

a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }

.intro {
  margin-bottom: 56px;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--rule);
  color: var(--muted);
}

.intro p { margin: 0 0 20px; }

[hidden] { display: none !important; }

/* filter bar */
.filter { margin: 0 0 48px; }

.search {
  width: 100%;
  margin-bottom: 16px;
  padding: 10px 14px;
  border: 1px solid var(--rule);
  border-radius: 8px;
  background: var(--bg);
  color: var(--fg);
  font-family: inherit;
  font-size: 0.95rem;
}

.search:focus { outline: 2px solid var(--link); outline-offset: -1px; }

.chips .chip { cursor: pointer; }

.chips .chip.is-active {
  background: var(--fg);
  color: var(--bg);
}

/* list entries */
.card {
  display: flex;
  gap: 24px;
  align-items: flex-start;
  margin: 0 0 56px;
}

.card-body { flex: 1; min-width: 0; }

.thumb { flex: 0 0 auto; }

.thumb img {
  display: block;
  width: 150px;
  height: 105px;
  border-radius: 4px;
  object-fit: cover;
}

.hero {
  display: block;
  width: 100%;
  height: auto;
  margin: 0 0 44px;
  border-radius: 6px;
}

.card h2 {
  margin: 0 0 6px;
  font-size: 1.45rem;
  line-height: 1.4;
  letter-spacing: -0.01em;
}

.card h2 a { color: var(--fg); }
.card h2 a:hover { color: var(--link); text-decoration: none; }

.meta {
  margin: 0 0 12px;
  color: var(--muted);
  font-size: 0.85rem;
  font-variant-numeric: tabular-nums;
}

.excerpt { margin: 0 0 14px; color: var(--muted); }

.empty { color: var(--muted); }

/* tag chips */
.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.tags a {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 999px;
  background: var(--chip-bg);
  color: var(--chip-fg);
  font-size: 0.78rem;
  line-height: 1.7;
}

.tags a:hover { color: var(--link); text-decoration: none; }

.taglist { margin-top: 4px; }

.tagtitle { margin: 0 0 40px; font-size: 1.6rem; }

/* article */
.post h1 {
  margin: 0 0 10px;
  font-size: 2.1rem;
  line-height: 1.35;
  letter-spacing: -0.02em;
}

.post .tags { margin-bottom: 40px; }

.prose > :first-child { margin-top: 0; }

.prose h2 { margin: 56px 0 14px; font-size: 1.5rem; line-height: 1.45; }
.prose h3 { margin: 40px 0 12px; font-size: 1.2rem; line-height: 1.5; }
.prose h4 { margin: 32px 0 10px; font-size: 1.05rem; }

.prose p { margin: 0 0 28px; }

.prose ul, .prose ol { margin: 0 0 28px; padding-left: 1.5em; }
.prose li { margin-bottom: 8px; }

.prose img, .prose video {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 36px auto;
  border-radius: 4px;
}

.prose hr {
  margin: 56px 0;
  border: 0;
  border-top: 1px solid var(--rule);
}

blockquote {
  margin: 32px 0;
  padding: 2px 0 2px 20px;
  border-left: 3px solid var(--quote-bar);
  color: var(--muted);
}

blockquote p:last-child { margin-bottom: 0; }

code {
  padding: 2px 6px;
  border-radius: 4px;
  background: var(--code-bg);
  font-family: var(--mono);
  font-size: 0.86em;
}

pre {
  max-width: 100%;
  margin: 0 0 28px;
  padding: 16px 18px;
  border-radius: 6px;
  background: var(--code-bg);
  overflow-x: auto;
  line-height: 1.6;
}

pre code {
  padding: 0;
  background: none;
  font-size: 0.84rem;
  white-space: pre;
}

.prose table {
  display: block;
  width: 100%;
  max-width: 100%;
  margin: 0 0 28px;
  overflow-x: auto;
  border-collapse: collapse;
  font-size: 0.92rem;
}

.prose th, .prose td {
  padding: 8px 14px;
  border-bottom: 1px solid var(--rule);
  text-align: left;
}

.prose th { font-weight: 600; }

/* katex overflow guard */
.katex-display { max-width: 100%; overflow-x: auto; overflow-y: hidden; padding: 4px 0; }

@media (max-width: 600px) {
  body { font-size: 17px; }
  header.site { padding-top: 36px; padding-bottom: 28px; }
  .post h1 { font-size: 1.7rem; }
  .card h2 { font-size: 1.3rem; }
  .card { flex-direction: column-reverse; gap: 16px; }
  .thumb, .thumb img { width: 100%; }
  .thumb img { height: 180px; }
}

/* mermaid diagrams */
.prose .mermaid {
  margin: 40px 0;
  padding: 0;
  background: none;
  font-family: var(--font);
  font-size: 0.9rem;
  line-height: 1.5;
  text-align: center;
  overflow-x: auto;
}

.prose .mermaid svg { max-width: 100%; height: auto; }

/* CSS-only bar chart. No library, no JavaScript. */
.bars {
  margin: 40px 0;
  padding: 0;
  font-size: 0.88rem;
}

.bars figcaption {
  margin-bottom: 18px;
  color: var(--muted);
  font-size: 0.82rem;
}

.bars .bar {
  display: grid;
  grid-template-columns: minmax(0, 11em) 1fr auto;
  gap: 12px;
  align-items: center;
  margin-bottom: 10px;
}

.bars .bar-label { color: var(--muted); }

.bars .bar-track {
  height: 12px;
  border-radius: 3px;
  background: var(--chip-bg);
}

.bars .bar-fill {
  display: block;
  min-width: 2px;
  height: 100%;
  border-radius: 3px;
  background: var(--link);
}

.bars .bar-value {
  font-variant-numeric: tabular-nums;
  text-align: right;
}

@media (max-width: 600px) {
  .bars .bar { grid-template-columns: minmax(0, 7.5em) 1fr auto; gap: 8px; }
  .bars { font-size: 0.8rem; }
}

/* CJK needs more leading than Latin; Latin-only pages tighten up. */
html[lang="en"] { --leading: 1.7; }

/* about timeline: same two-column grid language as .bars */
.timeline { margin: 32px 0 0; }

.timeline .tl {
  display: grid;
  grid-template-columns: 6.5em 1fr;
  gap: 20px;
  align-items: baseline;
  padding: 9px 0;
  border-top: 1px solid var(--rule);
}

.timeline .tl:last-child { border-bottom: 1px solid var(--rule); }

.timeline .tl-year {
  color: var(--muted);
  font-size: 0.82rem;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.timeline .tl-what { font-size: 0.95rem; }

.timeline .tl-where { color: var(--muted); }

@media (max-width: 600px) {
  .timeline .tl { grid-template-columns: 1fr; gap: 2px; padding: 12px 0; }
}