:root {
  --bg: #0d1117;
  --text: #c9d1d9;
  --accent: #58a6ff;
  --card: #161b22;
}
[data-theme="light"] {
  --bg: #ffffff;
  --text: #24292f;
  --accent: #0969da;
  --card: #f6f8fa;
}
html { scroll-behavior: smooth; }
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif; background: var(--bg); color: var(--text); margin:0; line-height:1.6; }
header { background: rgba(0,0,0,0.1); backdrop-filter: blur(10px); position: sticky; top:0; z-index:100; }
nav { max-width: 1000px; margin:0 auto; padding:1rem; display:flex; justify-content:space-between; align-items:center; flex-wrap:wrap; }
nav a { color: var(--text); text-decoration:none; margin:0 1rem; font-weight:500; }
nav a.logo { font-weight:800; font-size:1.3rem; color: var(--accent); }
nav a:hover { opacity:0.7; }
main { max-width: 800px; margin: 2rem auto; padding: 0 1rem; }
h1,h2,h3 { color: var(--accent); }
a { color: var(--accent); }
footer { text-align:center; padding:3rem; opacity:0.7; font-size:0.9rem; }
button { background:none; border:none; font-size:1.5rem; cursor:pointer; }
.card { background: var(--card); padding:1.5rem; border-radius:12px; margin:1.5rem 0; border:1px solid #30363d; }
[data-theme="light"] .card { border-color: #d0d7de; }