/* ---------- Design Tokens ---------- */
:root {
  --bg: #ffffff;
  --bg-elev: #fafafa;
  --border: #ececec;
  --text: #111111;
  --text-muted: #6b6b6b;
  --accent: #111111;
  --accent-contrast: #ffffff;
  --shadow: 0 1px 2px rgba(0,0,0,.04), 0 4px 12px rgba(0,0,0,.04);
  --radius: 12px;
  --max-w: 780px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "SF Mono", ui-monospace, Menlo, Consolas, monospace;
}

[data-theme="dark"] {
  --bg: #0e0e10;
  --bg-elev: #17171a;
  --border: #26262b;
  --text: #f1f1f2;
  --text-muted: #9a9aa2;
  --accent: #f1f1f2;
  --accent-contrast: #0e0e10;
  --shadow: 0 1px 2px rgba(0,0,0,.4), 0 4px 12px rgba(0,0,0,.3);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --bg: #0e0e10;
    --bg-elev: #17171a;
    --border: #26262b;
    --text: #f1f1f2;
    --text-muted: #9a9aa2;
    --accent: #f1f1f2;
    --accent-contrast: #0e0e10;
    --shadow: 0 1px 2px rgba(0,0,0,.4), 0 4px 12px rgba(0,0,0,.3);
  }
}

/* ---------- Reset ---------- */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  transition: background-color .25s ease, color .25s ease;
}
a { color: inherit; text-decoration: none; }
a:hover { opacity: .7; }
ul { list-style: none; padding: 0; margin: 0; }
img { max-width: 100%; display: block; }
h1, h2, h3 { font-weight: 700; letter-spacing: -0.02em; margin: 0; }

/* ---------- Layout ---------- */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: saturate(180%) blur(10px);
  -webkit-backdrop-filter: saturate(180%) blur(10px);
  background: color-mix(in oklab, var(--bg) 80%, transparent);
  border-bottom: 1px solid var(--border);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.brand {
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.02em;
}
.brand .dot { color: var(--text-muted); }
.nav-links {
  display: flex;
  gap: 28px;
  font-size: 0.95rem;
}
.nav-links a { color: var(--text-muted); }
.nav-links a:hover { color: var(--text); opacity: 1; }

.theme-toggle {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 999px;
  width: 36px; height: 36px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--text);
  cursor: pointer;
  transition: border-color .2s, background-color .2s;
}
.theme-toggle:hover { background: var(--bg-elev); }
.theme-toggle svg { width: 16px; height: 16px; }
.icon-sun, .icon-moon { display: none; }
[data-theme="light"] .icon-moon { display: block; }
[data-theme="dark"] .icon-sun { display: block; }
:root:not([data-theme]) .icon-moon { display: block; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) .icon-moon { display: none; }
  :root:not([data-theme]) .icon-sun { display: block; }
}

@media (max-width: 560px) {
  .nav-links { gap: 18px; font-size: 0.9rem; }
}

/* ---------- Hero ---------- */
.hero {
  padding: 96px 24px 48px;
}
.eyebrow {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin: 0 0 8px;
}
.hero h1 {
  font-size: clamp(2.2rem, 5vw, 3.4rem);
  margin-bottom: 16px;
}
.lede {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 620px;
  margin: 0 0 28px;
}
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }
.btn {
  display: inline-block;
  padding: 10px 18px;
  border-radius: 999px;
  font-size: 0.95rem;
  font-weight: 500;
  transition: transform .12s ease, background-color .2s ease, border-color .2s ease;
  border: 1px solid transparent;
}
.btn:hover { opacity: 1; transform: translateY(-1px); }
.btn-primary {
  background: var(--accent);
  color: var(--accent-contrast);
}
.btn-ghost {
  border-color: var(--border);
  color: var(--text);
}
.btn-ghost:hover { background: var(--bg-elev); }

/* ---------- Sections ---------- */
.section {
  padding: 56px 24px;
  border-top: 1px solid var(--border);
}
.section h2 {
  font-size: 1.5rem;
  margin-bottom: 24px;
}

/* About */
.about-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 32px;
  align-items: start;
}
.about-grid p { margin: 0; color: var(--text-muted); }
.facts {
  display: grid;
  gap: 10px;
  font-size: 0.95rem;
  color: var(--text-muted);
}
.facts li { display: flex; gap: 10px; align-items: center; }
@media (max-width: 640px) {
  .about-grid { grid-template-columns: 1fr; }
}

/* Projects */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}
.card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  transition: transform .15s ease, box-shadow .2s ease, border-color .2s ease;
}
.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}
.card h3 { font-size: 1.05rem; margin-bottom: 8px; }
.card p { color: var(--text-muted); margin: 0 0 14px; font-size: 0.95rem; }
.tags { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 14px; }
.tags span {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  padding: 2px 8px;
  border: 1px solid var(--border);
  border-radius: 999px;
}
.card-link { font-size: 0.9rem; color: var(--text); }

/* Blog */
.post-list li { border-top: 1px solid var(--border); }
.post-list li:first-child { border-top: none; }
.post-list a {
  display: flex;
  gap: 20px;
  padding: 16px 0;
  align-items: baseline;
  justify-content: space-between;
}
.post-list a:hover .post-title { text-decoration: underline; text-underline-offset: 4px; }
.post-date {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-muted);
  white-space: nowrap;
}
.post-title { font-size: 1rem; }
@media (max-width: 480px) {
  .post-list a { flex-direction: column; gap: 4px; }
}

/* Contact */
.contact-lede { color: var(--text-muted); margin: 0 0 20px; }
.socials { display: flex; flex-wrap: wrap; gap: 12px; }
.socials a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 0.9rem;
  transition: background-color .2s ease;
}
.socials a:hover { background: var(--bg-elev); opacity: 1; }
.socials svg { width: 16px; height: 16px; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 32px 0;
  color: var(--text-muted);
  font-size: 0.85rem;
  text-align: center;
}