/**
 * site.css — Distill-inspired unified styles for the main blog.
 * Covers: nav, pages, regular posts, home, archives, categories, footer.
 * Distill article posts use _layouts/distill.html + distill.css only.
 *
 * Design tokens match distill.css exactly so both files share the same
 * visual language and can evolve together.
 */

/* ── Design tokens ────────────────────────────────────────────────────────── */
:root {
  --accent:       #1565c0;
  --accent-light: #e8f0fe;
  --accent-warm:  #e65100;
  --text:         #1a1a1a;
  --text-light:   #444;
  --text-muted:   #777;
  --border:       #e0e0e0;
  --fig-bg:       #f8f9fb;
  --code-bg:      #1e2228;

  --serif:  'Merriweather', Georgia, serif;
  --sans:   'Source Sans 3', 'Helvetica Neue', sans-serif;
  --mono:   'JetBrains Mono', 'Fira Code', monospace;

  --content-w: 680px;
}

/* ── Reset ────────────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }
html { font-size: 16px; -webkit-text-size-adjust: 100%; }
body {
  margin: 0; padding: 0; background: #fff; color: var(--text); overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}
img { max-width: 100%; display: block; border-radius: 4px; }

/* ── Site navigation ──────────────────────────────────────────────────────── */
.site-nav {
  border-bottom: 1px solid var(--border);
  padding: 0 32px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  background: rgba(255,255,255,0.97);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 100;
  font-family: var(--sans);
}
.site-nav-brand {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: -0.015em;
  color: var(--text);
  text-decoration: none;
}
.site-nav-brand:hover { color: var(--accent); text-decoration: none; }

.site-nav-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 28px;
}
.site-nav-links a {
  font-size: 13px;
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 400;
  transition: color 0.1s;
}
.site-nav-links a:hover,
.site-nav-links a.active { color: var(--text); text-decoration: none; }

/*
 * Removed: the old `.site-main { max-width: 680px }` wrapper.
 * Every layout (post, page, distill) now provides its own .d-header and
 * .d-article — both centred at calc(--body-w + 32 + --gutter-w) (= 932px)
 * — so width is the layout's responsibility, not the shell's.
 * The home page still uses .site-main with body.home overrides; that rule
 * lives further down in this file.
 */

/* ── Global typography ────────────────────────────────────────────────────── */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--sans);
  color: var(--text);
  line-height: 1.25;
  font-weight: 700;
}

h1 {
  font-size: clamp(1.55rem, 3.5vw, 2rem);
  letter-spacing: -0.025em;
  margin: 0 0 0.4em;
}
h2 {
  font-size: 1.25rem;
  letter-spacing: -0.015em;
  margin: 2.4em 0 0.6em;
  padding-top: 0.5em;
  border-top: 1px solid var(--border);
}
h3 { font-size: 1.05rem; margin: 1.8em 0 0.4em; }
h4 { font-size: 0.95rem; margin: 1.2em 0 0.3em; }

/* Remove top border from first h2 inside page content */
.site-main > h2:first-child,
.page-body > h2:first-child,
.post-body > h2:first-child { border-top: none; padding-top: 0; margin-top: 1em; }

p {
  font-family: var(--serif);
  font-size: 0.975rem;
  line-height: 1.9;
  color: var(--text);
  margin: 0 0 1.2em;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
strong { font-weight: 700; }
em { font-style: italic; }

ul, ol {
  font-family: var(--serif);
  font-size: 0.975rem;
  line-height: 1.85;
  padding-left: 1.6em;
  margin-bottom: 1.2em;
}
li { margin-bottom: 0.3em; }

blockquote {
  border-left: 3px solid var(--accent);
  margin: 1.5em 0;
  padding: 0.6em 1.2em;
  background: var(--accent-light);
  font-style: italic;
  color: var(--text-light);
  font-family: var(--serif);
  font-size: 0.95rem;
}
blockquote p:last-child { margin-bottom: 0; }

hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2em 0;
}

/* ── Code ─────────────────────────────────────────────────────────────────── */
code {
  font-family: var(--mono);
  font-size: 0.84em;
  background: var(--fig-bg);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 1px 5px;
  color: var(--text);
}

pre {
  background: var(--code-bg);
  color: #abb2bf;
  border-radius: 6px;
  padding: 18px 20px;
  overflow-x: auto;
  margin: 1.5em 0;
  font-family: var(--mono);
  font-size: 0.82rem;
  line-height: 1.6;
  position: relative;
}
pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: inherit;
  color: inherit;
}

/* Copy button */
pre:hover button.copy { display: inline-block; }
button.copy {
  position: absolute;
  top: 0.75em;
  right: 0.75em;
  display: none;
  font-family: var(--sans);
  font-size: 11px;
  font-weight: 600;
  line-height: 20px;
  padding: 1px 7px;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.15);
  color: #888;
  border-radius: 3px;
  cursor: pointer;
}
button.copy:hover { background: rgba(255,255,255,0.15); color: #ddd; }

/* ── Tables (scoped to site-main to avoid conflicting with distill.css) ─── */
table { border-collapse: collapse; width: 100%; margin: 1.5em 0; }
.site-main table { display: block; overflow-x: auto; font-family: var(--sans); font-size: 0.9rem; }
.site-main thead { border-bottom: 2px solid var(--border); }
.site-main th {
  text-align: left;
  padding: 8px 12px;
  font-weight: 700;
  color: var(--text);
}
.site-main td {
  padding: 7px 12px;
  border-bottom: 1px solid var(--border);
  color: var(--text-light);
  font-family: var(--serif);
  font-size: 0.9rem;
  vertical-align: top;
}
.site-main tbody tr:last-child td { border-bottom: none; }

/* ── Math rendering ───────────────────────────────────────────────────────── */
.katex-display, .MathJax_Display {
  overflow-x: auto;
  margin: 1.4em 0;
}

/* ── Site footer ──────────────────────────────────────────────────────────── */
.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 0;
  padding: 20px 32px;
  font-family: var(--sans);
  font-size: 13px;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  max-width: var(--content-w);
  margin: 0 auto;
}
.site-footer a { color: var(--text-muted); text-decoration: underline; }
.site-footer a:hover { color: var(--text); }
.site-footer-social { display: flex; gap: 18px; }
.site-footer-social a { text-decoration: none; font-weight: 600; }

/* ── Page layout ──────────────────────────────────────────────────────────── */
.page-title {
  font-family: var(--sans);
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.025em;
  margin: 0 0 0.4em;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
  color: var(--text);
}
.page-body p,
.page-body li { /* inherits global */ }

/* ── Regular post layout ──────────────────────────────────────────────────── */
.post-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}
.post-header h1 { margin-bottom: 0.3em; }
.post-meta {
  font-family: var(--sans);
  font-size: 13px;
  color: var(--text-muted);
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  align-items: center;
  margin-top: 0.5em;
}
.post-meta a { color: var(--text-muted); text-decoration: underline; }
.post-meta-dot { opacity: 0.4; }
.post-read-time { font-size: 12px; }

.post-tags { display: flex; gap: 6px; flex-wrap: wrap; }
.post-tag {
  background: var(--fig-bg);
  border: 1px solid var(--border);
  color: var(--text-muted);
  border-radius: 3px;
  padding: 1px 7px;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.post-body { }
.post-body h2 { border-top: 1px solid var(--border); }

/* ── Related posts ────────────────────────────────────────────────────────── */
.related {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  font-family: var(--sans);
}
.related h2 {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  border-top: none;
  padding-top: 0;
  margin-top: 0;
  margin-bottom: 1rem;
}
.related-posts { list-style: none; padding: 0; margin: 0; }
.related-posts li { margin-bottom: 0.6em; display: flex; align-items: baseline; gap: 8px; }
.related-posts a { font-size: 0.9rem; color: var(--text); text-decoration: none; }
.related-posts a:hover { color: var(--accent); }
.related-posts small { font-size: 0.75rem; color: var(--text-muted); white-space: nowrap; }

/* ── Archive / tag listing (used by tag_index.html and similar) ──────────── */
.archive-list {
  list-style: none;
  padding: 0;
  margin: 0;
  font-family: var(--sans);
}
.archive-list li {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 10px;
  padding: 10px 0;
  border-bottom: 1px solid rgba(0,0,0,0.06);
}
.archive-list li:last-child { border-bottom: none; }
.archive-list a {
  font-size: 0.95rem;
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
}
.archive-list a:hover { color: var(--accent); }
.archive-list small {
  font-size: 0.75rem;
  color: var(--text-muted);
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}
.archive-tags {
  display: inline-flex;
  gap: 4px;
  flex-wrap: wrap;
  margin-left: auto;
}

/* ── Home page — 3-column distill-style listing ──────────────────────────── */

/*
 * meta (120px) | content (1fr ≈ 680px at 1100px wide) | media (220px)
 * 1100px = --body-w × φ.  Card padding 28px → ~56px gap between cards.
 * Separators: single hairline only, lighter than --border.
 */
body.home .site-main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 52px 48px 88px;
}
body.home .site-footer { max-width: 1100px; }

.home-card {
  position: relative;        /* anchor for the stretched-link ::after */
  display: grid;
  grid-template-columns: 120px 1fr;
  column-gap: 44px;
  padding: 28px 0;
  border-bottom: 1px solid rgba(0,0,0,0.07);
  cursor: pointer;
}
.home-card.has-media { grid-template-columns: 120px 1fr 220px; }
.home-card:last-child { border-bottom: none; }
.home-card:hover .home-card-title a { color: var(--accent); }

/*
 * Stretched link: the title's <a> is the semantic destination, but its
 * ::after pseudo-element covers the whole card so any click on the card
 * triggers navigation. Spans inside the card aren't links, so no conflict.
 */
.home-card-title a::after {
  content: "";
  position: absolute;
  inset: 0;
}

/*
 * 24px baseline grid for the card body.
 * Title, subtitle, description and every meta item share line-height: 24px,
 * and inter-block spacing is exactly 7px (title → subtitle, date → first meta).
 * So Date ↔ Title, Series-name ↔ Subtitle line 1, Series-part ↔ Subtitle line 2,
 * Read-time ↔ Subtitle line 3 — every meta item lines up with a content line.
 */

/* ── Meta column ── */
.home-card-meta {
  display: flex;
  flex-direction: column;
  gap: 0;            /* spacing comes from line-height + the date's margin-bottom */
}

/* "Apr'26" — same 7px gap below as title's margin-bottom */
.home-card-date {
  font-family: var(--sans);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: -0.015em;
  color: var(--text);
  white-space: nowrap;
  line-height: 24px;
  margin: 0 0 7px;
}

/* Series components flow as direct flex children of meta (no wrapper) */
.home-card-series-name {
  font-family: var(--sans);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent);
  line-height: 24px;
}
.home-card-series-part {
  font-family: var(--sans);
  font-size: 11px;
  color: var(--text-muted);
  line-height: 24px;
}
.home-card-cat {
  font-family: var(--sans);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  line-height: 24px;
}
.home-card-cat-inline {
  font-family: var(--sans);
  font-size: 0.69rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
}
.home-card-readtime {
  font-family: var(--sans);
  font-size: 11px;
  color: var(--text-muted);
  line-height: 24px;
}

/* ── Content column ── */
.home-card-body { min-width: 0; }

.home-card-title {
  font-family: var(--sans);
  font-size: 1.18rem;        /* ≈18.9px */
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 24px;         /* matches meta baseline */
  color: var(--text);
  margin: 0 0 7px;           /* matches .home-card-date margin-bottom */
  border-top: none;
  padding-top: 0;
}
.home-card-title a {
  color: inherit;
  text-decoration: none;
  transition: color 0.1s;
}
.home-card-title a:hover { color: var(--accent); }

.home-card-subtitle {
  font-family: var(--serif);
  font-size: 0.9rem;         /* ≈14.4px */
  font-style: italic;
  color: var(--text-light);
  line-height: 24px;         /* matches meta baseline */
  margin: 0 0 7px;           /* keep rhythm into description */
}
.home-card-desc {
  font-family: var(--sans);
  font-size: 0.84rem;        /* ≈13.4px */
  color: var(--text-muted);
  line-height: 24px;         /* keep rhythm — 3-line clamp fits cleanly */
  margin: 0 0 12px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.home-card-footer {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}
.home-card-tags { display: flex; gap: 5px; flex-wrap: wrap; }
.home-card-tag {
  font-family: var(--sans);
  font-size: 0.69rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  background: var(--accent-light);
  color: var(--accent);
  border-radius: 3px;
  padding: 2px 7px;
}
/* ── Media column ── */
.home-card-media { align-self: start; }
.home-card-media img {
  width: 100%;
  height: 140px;
  object-fit: contain;
  border-radius: 0;
  border: none;
  background: transparent;
}

/* ── Responsive ── */
@media (max-width: 960px) {
  body.home .site-main { padding: 44px 32px 72px; }
  .home-card { grid-template-columns: 96px 1fr; column-gap: 28px; }
  .home-card.has-media { grid-template-columns: 96px 1fr 140px; column-gap: 24px; }
  .home-card-media img { height: 110px; }
}
@media (max-width: 640px) {
  /*
   * Mobile layout — image becomes a hero banner stacked above the meta
   * row and body. Single column, so [media | body] never crowd each other.
   */
  body.home .site-main { padding: 28px 18px 52px; }
  .home-card,
  .home-card.has-media {
    grid-template-columns: 1fr;
    grid-template-areas:
      "media"
      "meta"
      "body";
    row-gap: 10px;
  }
  .home-card:not(.has-media) {
    grid-template-areas:
      "meta"
      "body";
  }
  .home-card-meta {
    grid-area: meta;
    flex-direction: row;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 0;
  }
  .home-card-body { grid-area: body; }
  .home-card-media {
    grid-area: media;
    align-self: stretch;
  }
  .home-card-media img {
    width: 100%;
    height: 160px;
    object-fit: contain;
  }
  .home-card-date { margin-bottom: 0; }
  .home-card-readtime { display: none; }
  .home-card-title { font-size: 1.05rem; }
}

/* ── Pagination ───────────────────────────────────────────────────────────── */
.pagination {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  font-family: var(--sans);
  font-size: 13px;
}
.pagination-item {
  color: var(--accent);
  text-decoration: none;
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: 4px;
  cursor: pointer;
}
.pagination-item:hover { background: var(--accent-light); border-color: var(--accent); text-decoration: none; }
span.pagination-item { color: var(--text-muted); cursor: default; }
span.pagination-item:hover { background: none; border-color: var(--border); }

/* ── Archives & Categories ────────────────────────────────────────────────── */
.tag_box {
  list-style: none;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 2.5rem;
}
.tag_box li { display: inline; }
.tag_box a {
  display: inline-block;
  background: var(--fig-bg);
  border: 1px solid var(--border);
  color: var(--text-light);
  font-family: var(--sans);
  font-size: 0.8rem;
  padding: 3px 10px;
  border-radius: 4px;
  text-decoration: none;
}
.tag_box a:hover { background: var(--accent-light); color: var(--accent); border-color: var(--accent-light); text-decoration: none; }
.tag_box span { font-size: 0.7rem; color: var(--text-muted); margin-left: 2px; }

/* ── Responsive ───────────────────────────────────────────────────────────── */
@media (max-width: 720px) {
  .site-nav { padding: 0 20px; }
  body:not(.home) .site-main { padding: 32px 20px 60px; }
  .site-footer { padding: 16px 20px; }
}
@media (max-width: 520px) {
  .site-nav-links { gap: 16px; }
  .site-nav-links a { font-size: 12px; }
}