/* ===== design tokens (copied from original demo) ===== */
:root {
  --bg: #FAFAF9;
  --bg2: #FFFFFF;
  --ink: #1C1917;
  --muted: #78716C;
  --rule: #E7E5E4;
  --accent: #0369A1;
  --accent2: #0EA5E9;
  --warm: #EA580C;
  --tag-blog: #DC2626;
  --tag-knowledge: #0369A1;

  --serif: Georgia, 'Times New Roman', 'Songti SC', 'STSong', serif;
  --sans: -apple-system, BlinkMacSystemFont, 'Helvetica Neue', 'PingFang SC', 'Microsoft YaHei', 'Helvetica', Arial, sans-serif;
  --mono: 'SF Mono', Menlo, Monaco, Consolas, 'Courier New', monospace;
}

/* ===== reset ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; transition: color .15s; }
a:hover { color: var(--ink); text-decoration: underline; text-underline-offset: 2px; }
button { border: none; background: none; cursor: pointer; font-family: inherit; }
img { max-width: 100%; height: auto; }
code, pre { font-family: var(--mono); font-size: 0.9em; }

/* ===== nav ===== */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(250,250,249,0.92);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--rule);
}
.nav-inner {
  max-width: 1080px; margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex; align-items: center; justify-content: space-between;
}
.nav-logo {
  font-family: var(--serif); font-style: italic;
  font-size: 1.4rem; color: var(--ink);
  letter-spacing: -0.01em; font-weight: 400;
}
.nav-logo:hover { text-decoration: none; }
.nav-links { display: flex; gap: 1.75rem; align-items: center; }
.nav-links a {
  font-size: 0.9rem; color: var(--muted);
  transition: color .15s;
}
.nav-links a:hover { color: var(--ink); text-decoration: none; }
.nav-links a.active { color: var(--ink); font-weight: 700; }

/* ===== containers & sections ===== */
.container { max-width: 1080px; margin: 0 auto; padding: 0 1.5rem; }
.section { padding: 3rem 0; border-top: 1px solid var(--rule); }
.section-title {
  font-family: var(--mono);
  font-size: 0.78rem; font-weight: 400;
  letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 1.5rem;
  display: flex; align-items: center; gap: 0.75rem;
}
.section-title::before {
  content: ''; width: 4px; height: 14px; background: var(--accent);
  display: inline-block;
}

/* ===== hero ===== */
.hero { padding: 4.5rem 0 3rem; text-align: center; }
.hero-eyebrow {
  font-family: var(--mono);
  font-size: 0.72rem; letter-spacing: 0.2em;
  color: var(--muted); text-transform: uppercase;
  margin-bottom: 1.5rem;
}
.hero h1 {
  font-family: var(--serif); font-style: italic;
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 400;
  letter-spacing: -0.02em;
  line-height: 1.05;
  margin-bottom: 1.5rem;
}
.hero-subtitle {
  max-width: 640px; margin: 0 auto 1.25rem;
  font-size: 1.05rem; color: var(--muted); line-height: 1.7;
}
.hero-cta {
  display: flex; gap: 0.75rem; justify-content: center;
  margin-top: 2rem; flex-wrap: wrap;
}
.btn {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.65rem 1.25rem; border-radius: 999px;
  font-size: 0.9rem; font-weight: 500;
  transition: all .15s ease;
}
.btn-primary { background: var(--ink); color: var(--bg2); }
.btn-primary:hover { background: #000; transform: translateY(-1px); text-decoration: none; color: var(--bg2); }
.btn-ghost { background: transparent; color: var(--ink); border: 1px solid var(--rule); }
.btn-ghost:hover { border-color: var(--ink); text-decoration: none; }

/* ===== stats ===== */
.stats {
  display: grid; grid-template-columns: repeat(4, 1fr);
  gap: 1px; background: var(--rule);
  border: 1px solid var(--rule); border-radius: 12px;
  overflow: hidden; margin: 0 auto; max-width: 720px;
}
.stat-cell { background: var(--bg2); padding: 1.5rem 1rem; text-align: center; }
.stat-num {
  font-family: var(--serif);
  font-size: 2rem; font-weight: 400;
  letter-spacing: -0.02em; color: var(--ink);
  display: block; line-height: 1.1;
}
.stat-num .unit {
  font-size: 1rem; color: var(--muted);
  margin-left: 2px; font-family: var(--mono);
}
.stat-label {
  font-family: var(--mono);
  font-size: 0.72rem; letter-spacing: 0.08em;
  color: var(--muted); text-transform: uppercase;
  margin-top: 0.5rem; display: block;
}

/* ===== personal intro ===== */
.personal { text-align: center; padding: 2rem 0; }
.personal h2 {
  font-family: var(--serif); font-style: italic;
  font-size: 1.5rem; font-weight: 400;
  margin-bottom: 0.75rem; letter-spacing: -0.01em;
}
.personal p { max-width: 580px; margin: 0 auto; color: var(--muted); font-size: 0.95rem; }

/* ===== recent list ===== */
.recent-list { display: flex; flex-direction: column; gap: 0; border-top: 1px solid var(--rule); }
.recent-item {
  display: grid;
  grid-template-columns: 90px 1fr auto;
  gap: 1.5rem;
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--rule);
  align-items: start;
  transition: background .15s;
}
.recent-item:hover { background: rgba(0,0,0,0.015); }
.recent-item:hover .recent-title { color: var(--accent); }
.recent-item:hover { text-decoration: none; }
.recent-type {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.7rem; letter-spacing: 0.06em;
  padding: 0.2rem 0.55rem; border-radius: 4px;
  text-align: center; white-space: nowrap;
  background: rgba(3,105,161,0.08);
  color: var(--tag-knowledge);
}
.recent-type.blog { background: rgba(220,38,38,0.08); color: var(--tag-blog); }
.recent-body { min-width: 0; }
.recent-title { font-size: 1rem; font-weight: 700; margin-bottom: 0.35rem; line-height: 1.4; color: var(--ink); transition: color .15s; }
.recent-desc { color: var(--muted); font-size: 0.88rem; line-height: 1.5; }
.recent-meta {
  font-family: var(--mono);
  font-size: 0.78rem; color: var(--muted);
  white-space: nowrap;
  text-align: right;
  padding-top: 0.15rem;
}

/* ===== heatmap ===== */
.heatmap-wrap {
  background: var(--bg2);
  border: 1px solid var(--rule);
  border-radius: 12px;
  padding: 1.5rem;
  overflow-x: auto;
}
.heatmap-header {
  display: flex; justify-content: space-between; align-items: baseline;
  margin-bottom: 1rem; flex-wrap: wrap; gap: 0.5rem;
}
.heatmap-title { font-size: 0.92rem; font-weight: 700; }
.heatmap-legend {
  display: flex; align-items: center; gap: 0.4rem;
  font-family: var(--mono);
  font-size: 0.7rem; color: var(--muted);
}
.heatmap-legend .cell { width: 11px; height: 11px; border-radius: 2px; background: var(--rule); display: inline-block; }
.heatmap-svg { display: block; max-width: 100%; height: auto; }
.heatmap-cell { stroke: rgba(255,255,255,0.6); stroke-width: 1; rx: 2; }
.heatmap-days { font-family: var(--mono); font-size: 10px; fill: var(--muted); }

/* ===== tags cloud ===== */
.tags { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.tag {
  display: inline-flex; align-items: center;
  padding: 0.35rem 0.85rem;
  background: var(--bg2);
  border: 1px solid var(--rule);
  border-radius: 999px;
  font-size: 0.85rem; color: var(--ink);
  transition: all .15s;
}
.tag:hover {
  border-color: var(--ink);
  transform: translateY(-1px);
  text-decoration: none;
}
.tag .count { font-family: var(--mono); font-size: 0.72rem; color: var(--muted); margin-left: 0.4rem; }

/* ===== knowledge/categories grid ===== */
.knowledge-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}
.knowledge-card {
  background: var(--bg2);
  border: 1px solid var(--rule);
  border-radius: 12px;
  padding: 1.5rem;
  transition: all .2s;
  color: var(--ink);
}
.knowledge-card:hover {
  border-color: var(--ink);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px -10px rgba(0,0,0,0.1);
  text-decoration: none;
}
.knowledge-card-title { font-size: 1.05rem; font-weight: 700; margin-bottom: 0.5rem; }
.knowledge-card-desc {
  color: var(--muted); font-size: 0.85rem;
  line-height: 1.5; margin-bottom: 1rem;
  min-height: 2.5em;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.knowledge-card-meta {
  font-family: var(--mono);
  font-size: 0.74rem; color: var(--muted);
  display: flex; gap: 1rem;
  border-top: 1px solid var(--rule);
  padding-top: 0.75rem;
}
.knowledge-card-meta strong { color: var(--ink); font-weight: 700; }

/* ===== footer ===== */
.footer {
  border-top: 1px solid var(--rule);
  padding: 2.5rem 0 2rem;
  margin-top: 3rem;
}
.footer-inner {
  display: flex; justify-content: space-between; align-items: center;
  flex-wrap: wrap; gap: 1rem;
}
.footer-copy { font-family: var(--mono); font-size: 0.78rem; color: var(--muted); }
.footer-links { display: flex; gap: 1.5rem; }
.footer-links a { font-size: 0.85rem; color: var(--muted); }
.footer-links a:hover { color: var(--ink); }

/* ===== archive / list pages ===== */
.archive-list { display: flex; flex-direction: column; }
.archive-year {
  font-family: var(--mono);
  font-size: 0.85rem; font-weight: 700;
  color: var(--muted);
  margin: 1.5rem 0 0.5rem;
  letter-spacing: 0.1em;
}
.archive-year:first-child { margin-top: 0; }
.archive-item {
  display: flex;
  gap: 1rem;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--rule);
}
.archive-item time {
  font-family: var(--mono); font-size: 0.78rem;
  color: var(--muted); flex-shrink: 0;
  min-width: 90px;
  padding-top: 0.15rem;
}
.archive-item a { color: var(--ink); flex: 1; }
.archive-item a:hover { color: var(--accent); }

/* ===== tag / category detail pages ===== */
.page-header { padding: 3rem 0 2rem; border-bottom: 1px solid var(--rule); margin-bottom: 1rem; }
.page-header h1 { font-family: var(--serif); font-style: italic; font-size: 2rem; font-weight: 400; margin-bottom: 0.5rem; }
.page-header .page-meta { color: var(--muted); font-size: 0.85rem; }

/* ===== post detail page ===== */
.post {
  padding: 3rem 0 2rem;
  max-width: 760px;
}
.post-header { margin-bottom: 2.5rem; padding-bottom: 1.5rem; border-bottom: 1px solid var(--rule); }
.post-title {
  font-family: var(--serif);
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 400;
  line-height: 1.2;
  margin-bottom: 1rem;
  letter-spacing: -0.01em;
}
.post-meta {
  display: flex; gap: 1rem; flex-wrap: wrap;
  font-family: var(--mono); font-size: 0.82rem;
  color: var(--muted); align-items: center;
}
.post-meta a { color: var(--muted); }
.post-meta a:hover { color: var(--accent); }
.post-meta .dot { color: var(--rule); }

.post-content { font-size: 1.02rem; line-height: 1.85; color: var(--ink); }
.post-content > * + * { margin-top: 1.25rem; }
.post-content h2 { font-size: 1.5rem; font-weight: 700; margin-top: 2.5rem; margin-bottom: 0.5rem; line-height: 1.3; }
.post-content h3 { font-size: 1.2rem; font-weight: 700; margin-top: 2rem; margin-bottom: 0.5rem; line-height: 1.3; }
.post-content h4 { font-size: 1.05rem; font-weight: 700; margin-top: 1.5rem; margin-bottom: 0.25rem; }
.post-content p { margin-bottom: 1.25rem; }
.post-content ul, .post-content ol { padding-left: 1.5rem; margin-bottom: 1.25rem; }
.post-content li { margin-bottom: 0.4rem; }
.post-content blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.25rem 1rem;
  color: var(--muted);
  font-style: italic;
  background: rgba(3,105,161,0.04);
  border-radius: 0 4px 4px 0;
}
.post-content code {
  background: var(--bg2);
  border: 1px solid var(--rule);
  padding: 0.1rem 0.35rem;
  border-radius: 3px;
  font-size: 0.88em;
  color: var(--ink);
}
.post-content pre {
  background: var(--bg2);
  border: 1px solid var(--rule);
  padding: 1rem;
  border-radius: 8px;
  overflow-x: auto;
  margin: 1.5rem 0;
}
.post-content pre code { background: none; border: none; padding: 0; font-size: 0.85em; }
.post-content hr { border: none; border-top: 1px solid var(--rule); margin: 2.5rem 0; }
.post-content img { border-radius: 8px; margin: 1.5rem 0; }
.post-content table { border-collapse: collapse; margin: 1.5rem 0; font-size: 0.92rem; }
.post-content th, .post-content td { padding: 0.5rem 0.75rem; border: 1px solid var(--rule); }
.post-content th { background: var(--bg2); font-weight: 700; }

.post-footer {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
  display: flex; gap: 0.5rem; flex-wrap: wrap;
}

.post-nav {
  display: flex; justify-content: space-between;
  gap: 1rem; padding: 1.5rem 0;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  font-size: 0.9rem;
}
.post-nav a { color: var(--muted); flex: 1; max-width: 45%; }
.post-nav a:hover { color: var(--accent); }
.post-nav .next { text-align: right; }

/* ===== empty state ===== */
.empty {
  padding: 3rem 0;
  text-align: center;
  color: var(--muted);
  font-size: 0.95rem;
}

/* ===== responsive ===== */
@media (max-width: 768px) {
  .hero { padding: 3rem 0 2rem; }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .stat-num { font-size: 1.6rem; }
  .recent-item { grid-template-columns: 1fr; gap: 0.5rem; }
  .recent-meta { text-align: left; padding-top: 0; }
  .nav-links { gap: 1rem; font-size: 0.85rem; }
  .nav-links a:nth-child(4) { display: none; }
  .post-content { font-size: 0.98rem; }
}
@media (max-width: 480px) {
  .knowledge-grid { grid-template-columns: 1fr; }
  .nav-links a:nth-child(3) { display: none; }
}