/* ===== Design tokens (matching home.fanjiang.net) ===== */
:root {
  --bg:          #F2EEE5;
  --bg-raised:   #FAF7F0;
  --ink:         #1F1B16;
  --ink-muted:   #6B5D4F;
  --ink-faint:   #A39385;
  --rule:        #D9D0C1;
  --accent:      #92400E;
  --accent-warm: #B45309;
  --callout-bg:  #FBF2D9;

  --font-display: "Crimson Pro", "Source Serif 4", "Noto Serif SC", Georgia, serif;
  --font-body:    "Source Serif 4", "Crimson Pro", "Noto Serif SC", Georgia, serif;
  --font-mono:    "IBM Plex Mono", "JetBrains Mono", ui-monospace, "SF Mono", Menlo, monospace;

  --fs-display: clamp(2.25rem, 4vw + 1rem, 3rem);
  --fs-h2:      1.5rem;
  --fs-body:    1.0625rem;
  --fs-meta:    0.8125rem;
  --lh-body:    1.7;
  --lh-display: 1.1;
}

[data-theme="dark"] {
  --bg:          #1C1814;
  --bg-raised:   #252017;
  --ink:         #F2EEE5;
  --ink-muted:   #B8A890;
  --ink-faint:   #6B5D4F;
  --rule:        #3A3228;
  --accent:      #D97706;
  --accent-warm: #F59E0B;
  --callout-bg:  #2D2516;
}

/* ===== Base reset ===== */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  font-feature-settings: "kern" 1, "liga" 1, "calt" 1;
  transition: background-color 300ms ease, color 300ms ease;
}

img { max-width: 100%; height: auto; }

/* ===== Layout ===== */
.site-wrapper {
  max-width: 740px;
  margin: 0 auto;
  padding: 4rem clamp(1.25rem, 5vw, 2rem) 6rem;
}
@media (max-width: 640px) {
  .site-wrapper { padding-top: 2.5rem; padding-bottom: 4rem; }
}

/* ===== Theme toggle ===== */
.theme-bar {
  position: fixed;
  top: 1.25rem;
  right: 1.25rem;
  z-index: 100;
}
.theme-toggle {
  width: 40px; height: 40px;
  border-radius: 50%;
  background: var(--bg-raised);
  border: 1px solid var(--rule);
  color: var(--ink);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  transition: background 200ms ease, border-color 200ms ease, color 200ms ease;
}
.theme-toggle:hover { border-color: var(--accent); color: var(--accent); }
.theme-toggle:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.theme-toggle svg { width: 18px; height: 18px; }
.theme-toggle .icon-sun { display: none; }
[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }

/* ===== Header ===== */
.site-header {
  margin-bottom: 3rem;
}
.site-title {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3vw + 0.5rem, 2.25rem);
  font-weight: 500;
  letter-spacing: -0.02em;
  margin: 0 0 0.25rem;
}
.site-title a {
  color: var(--ink);
  text-decoration: none;
}
.site-title a:hover { color: var(--accent); }

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  margin-top: 0.75rem;
}
.site-nav a {
  font-family: var(--font-mono);
  font-size: var(--fs-meta);
  color: var(--ink-muted);
  text-decoration: none;
  transition: color 150ms ease;
}
.site-nav a:hover { color: var(--accent); }

/* ===== Typography ===== */
h1, h2, h3 {
  font-family: var(--font-display);
  color: var(--ink);
}

.post-title {
  font-size: var(--fs-display);
  font-weight: 500;
  line-height: var(--lh-display);
  letter-spacing: -0.02em;
  margin: 0 0 0.5rem;
}

.post-meta {
  font-family: var(--font-mono);
  font-size: var(--fs-meta);
  color: var(--ink-muted);
  margin-bottom: 2.5rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.4rem;
}

.post-meta .tag {
  display: inline-block;
  background: var(--callout-bg);
  color: var(--accent);
  padding: 0.15em 0.5em;
  border-radius: 3px;
  font-size: 0.75rem;
  margin-left: 0.25rem;
}

/* ===== Links ===== */
a {
  color: var(--ink);
  text-decoration: underline;
  text-decoration-color: var(--ink-faint);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: color 150ms ease, text-decoration-color 150ms ease;
}
a:hover {
  color: var(--accent);
  text-decoration-color: var(--accent);
}

/* ===== Post list (home) ===== */
.post-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 2rem;
}
.post-list-item {
  border-bottom: 1px solid var(--rule);
  padding-bottom: 2rem;
}
.post-list-item:last-child { border-bottom: none; }

.post-list-title {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 500;
  margin: 0 0 0.35rem;
  letter-spacing: -0.01em;
}
.post-list-title a {
  text-decoration: none;
  color: var(--ink);
}
.post-list-title a:hover { color: var(--accent); }

.post-list-meta {
  font-family: var(--font-mono);
  font-size: var(--fs-meta);
  color: var(--ink-faint);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.4rem;
}
.meta-sep { color: var(--rule); }

.post-list-summary {
  color: var(--ink-muted);
  margin: 0.5rem 0 0;
  line-height: 1.6;
}

/* ===== Article content ===== */
.post-content h2 {
  font-size: var(--fs-h2);
  font-weight: 600;
  margin: 2.5rem 0 1rem;
  letter-spacing: -0.01em;
}
.post-content h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 2rem 0 0.75rem;
}
.post-content p { margin: 0 0 1.25em; }
.post-content ul, .post-content ol {
  margin: 0 0 1.25em;
  padding-left: 1.5em;
}
.post-content li { margin-bottom: 0.35em; }

.post-content blockquote {
  background: var(--callout-bg);
  border-left: 3px solid var(--accent-warm);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  font-style: italic;
  color: var(--ink);
  transition: background-color 300ms ease;
}
.post-content blockquote p:last-child { margin-bottom: 0; }

.post-content code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--bg-raised);
  padding: 0.15em 0.35em;
  border-radius: 3px;
  border: 1px solid var(--rule);
}
.post-content pre {
  background: var(--bg-raised);
  border: 1px solid var(--rule);
  border-radius: 6px;
  padding: 1.25rem;
  overflow-x: auto;
  margin: 1.5rem 0;
  transition: background-color 300ms ease, border-color 300ms ease;
}
.post-content pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: 0.85rem;
  line-height: 1.6;
}

.post-content img {
  border-radius: 6px;
  margin: 1.5rem 0;
}

.post-content hr {
  border: none;
  border-top: 1px solid var(--rule);
  margin: 2.5rem 0;
}

/* ===== Footer ===== */
.site-footer {
  margin-top: 4rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
  font-family: var(--font-mono);
  font-size: var(--fs-meta);
  color: var(--ink-faint);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.site-footer a {
  color: var(--ink-muted);
  text-decoration: none;
}
.site-footer a:hover { color: var(--accent); }

/* ===== Pagination ===== */
.pagination {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
  font-family: var(--font-mono);
  font-size: var(--fs-meta);
}
.pagination a {
  color: var(--ink-muted);
  text-decoration: none;
}
.pagination a:hover { color: var(--accent); }

/* ===== Back link ===== */
.back-link {
  font-family: var(--font-mono);
  font-size: var(--fs-meta);
  color: var(--ink-muted);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  margin-bottom: 2rem;
}
.back-link:hover { color: var(--accent); }