:root{
  --logo-h:72px;
  --bg:#ffffff;
  --text:#0f172a;
  --muted:#64748b;
  --brand:#1f3a8a;
  --brand-2:#3b82f6;
  --card:#f8fafc;
  --border:#e5e7eb;
  --code-bg:#0b1020;
  --code-fg:#cbd5e1;
  --radius:14px;
}
html[data-theme="dark"]{
  --bg:#0b1220;
  --text:#e5e7eb;
  --muted:#94a3b8;
  --brand:#93c5fd;
  --brand-2:#60a5fa;
  --card:#0f172a;
  --border:#1f2937;
  --code-bg:#0a0f1a;
  --code-fg:#e2e8f0;
}
*{box-sizing:border-box}
html,body{margin:0;padding:0;background:var(--bg);color:var(--text);font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,Arial,Noto Sans,'Helvetica Neue',sans-serif;}
a{color:var(--brand-2);text-decoration:none}a:hover{text-decoration:underline}
.container{max-width:1200px;margin:0 auto;padding:24px}
.nav{position:sticky;top:0;z-index:10;background:rgba(255,255,255,.8);backdrop-filter:blur(8px);border-bottom:1px solid var(--border)}
html[data-theme="dark"] .nav{background:rgba(11,18,32,.8)}
.nav-inner{display:flex;align-items:center;gap:16px;padding:6px 24px}
.nav .logo{display:flex;align-items:center;gap:12px}
.nav .links{display:flex;gap:16px;flex-wrap:wrap}
.nav input[type=search]{flex:1;min-width:180px;border:1px solid var(--border);border-radius:999px;padding:10px 14px;background:var(--bg);color:var(--text)}
.theme-toggle{margin-left:auto;border:1px solid var(--border);background:var(--card);color:var(--text);padding:8px 12px;border-radius:999px;cursor:pointer}
.badge{background:linear-gradient(135deg,var(--brand-2),#22d3ee);color:white;padding:6px 10px;border-radius:999px;font-size:12px;font-weight:700;letter-spacing:.4px}
.hero{display:grid;grid-template-columns:1.1fr .9fr;gap:28px;align-items:center;padding:36px 0}
.hero .title{font-size:44px;line-height:1.1;margin:0}
.hero .subtitle{color:var(--muted);font-size:18px}
.cta{display:flex;gap:12px;margin-top:16px}
.btn{border:none;border-radius:12px;padding:12px 16px;font-weight:700;cursor:pointer}
.btn.primary{background:linear-gradient(135deg,#1fb6ff,#3b82f6);color:white}
.btn.ghost{background:transparent;border:1px solid var(--border);color:var(--text)}
.grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:18px;transition:transform .15s ease, box-shadow .15s ease}
.card:hover{transform:translateY(-2px);box-shadow:0 6px 24px rgba(2,6,23,.12)}
.card .kicker{font-size:12px;color:var(--muted)}
.card h3{margin:6px 0 8px 0;font-size:18px}
.footer{border-top:1px solid var(--border);padding:22px 0;color:var(--muted)}
.page{display:grid;grid-template-columns:280px 1fr;gap:24px}
.sidebar{position:sticky;top:68px;height:calc(100vh - 88px);overflow:auto;border-right:1px solid var(--border);padding-right:10px}
.sidebar h4{margin:12px 0 8px 0}
.sidebar a{display:block;padding:8px 10px;border-radius:8px;color:var(--text)}
.sidebar a.active,.sidebar a:hover{background:#1e293b1a}
.article{min-width:0}
.article h1{font-size:34px;margin-top:0}
.article pre{background:var(--code-bg);color:var(--code-fg);border-radius:12px;padding:14px;overflow:auto}
.article code{font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace}
.kbd{border:1px solid var(--border);border-bottom-width:3px;padding:2px 6px;border-radius:6px;background:var(--bg)}
.search-results{display:grid;grid-template-columns:1fr;gap:12px;margin-top:18px}
.search-results a{display:block;border:1px solid var(--border);border-radius:12px;padding:14px;background:var(--card)}
.quiz{max-width:760px}
.quiz .q{border:1px solid var(--border);border-radius:12px;padding:14px;margin:12px 0;background:var(--card)}
.quiz .choices label{display:block;margin:8px 0;padding:8px;border:1px solid var(--border);border-radius:8px;cursor:pointer}
.quiz .correct{outline:2px solid #22c55e}
.quiz .wrong{outline:2px solid #ef4444}
@media (max-width:1020px){.grid{grid-template-columns:repeat(2,1fr)}.hero{grid-template-columns:1fr} .page{grid-template-columns:1fr} .sidebar{position:relative;height:auto;border-right:none;padding-right:0}}

.nav .logo img{height:var(--logo-h);width:auto;display:block}

@media (max-width:600px){.nav .logo img{height:40px}}