:root{
  --bg:#f8fafc;
  --surface:#ffffff;
  --text:#0f172a;
  --muted:#475569;
  --border:#e2e8f0;
  --accent:#2563eb;
  --accent-dark:#1d4ed8;
  --code-bg:#0f172a;
  --code-text:#e2e8f0;
  --maxw:1320px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:Arial, Helvetica, sans-serif;
  background:var(--bg);
  color:var(--text);
  line-height:1.75;
}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
.layout{
  max-width:var(--maxw);
  margin:0 auto;
  display:grid;
  grid-template-columns:320px 1fr;
  gap:28px;
  padding:24px 18px 44px;
}
.sidebar{
  position:sticky;
  top:16px;
  align-self:start;
  background:var(--surface);
  border:1px solid var(--border);
  border-radius:20px;
  padding:20px;
  box-shadow:0 12px 30px rgba(15,23,42,.06);
  max-height:calc(100vh - 32px);
  overflow:auto;
}
.brand{display:block;color:var(--text);margin-bottom:18px}
.brand h1{margin:0 0 8px;font-size:24px;line-height:1.12}
.brand p{margin:0;font-size:14px;color:var(--muted)}
.sidebar h2{
  margin:18px 0 10px;
  font-size:14px;
  color:var(--muted);
  text-transform:uppercase;
  letter-spacing:.04em;
}
.sidebar ol{margin:0;padding-left:20px}
.sidebar li{margin:7px 0}
.sidebar a{color:#1e293b;font-size:14px}
.sidebar a.active{color:var(--accent-dark);font-weight:700}
.content{min-width:0}
.hero,.article{
  background:var(--surface);
  border:1px solid var(--border);
  border-radius:22px;
  box-shadow:0 12px 30px rgba(15,23,42,.05);
}
.hero{
  padding:30px;
  margin-bottom:22px;
  background:linear-gradient(180deg,#fff,#f8fbff);
}
.hero h1{margin:0 0 12px;font-size:42px;line-height:1.08}
.hero p{margin:0;color:var(--muted);font-size:18px}
.article{padding:36px}
.article h1{margin:0 0 18px;font-size:40px;line-height:1.1}
.article h2{margin:38px 0 14px;font-size:31px;line-height:1.2}
.article h3{margin:26px 0 10px;font-size:24px;line-height:1.25}
.article p{margin:0 0 16px}
.article ul,.article ol{margin:0 0 18px 24px;padding:0}
.article li{margin:7px 0}
.lead{font-size:19px;color:#1e293b}
.note,.tip,.warn{margin:20px 0;padding:14px 16px;border-radius:14px}
.note{background:#eff6ff;border-left:4px solid #3b82f6}
.tip{background:#f0fdf4;border-left:4px solid #22c55e}
.warn{background:#fff7ed;border-left:4px solid #f97316}
pre{
  background:var(--code-bg);
  color:var(--code-text);
  padding:16px;
  border-radius:14px;
  overflow:auto;
  font-size:14px;
  line-height:1.58;
  border:1px solid #1e293b;
  margin:16px 0 18px;
}
code{font-family:Consolas, Monaco, monospace}
.nav{
  display:flex;
  gap:16px;
  justify-content:space-between;
  margin-top:34px;
}
.nav a,.nav div{
  flex:1;
  border:1px solid var(--border);
  border-radius:14px;
  background:#fafcff;
  padding:14px 16px;
  color:var(--text);
}
.nav small{display:block;color:var(--muted);margin-bottom:6px}
@media (max-width:980px){
  .layout{grid-template-columns:1fr}
  .sidebar{position:relative;top:auto;max-height:none}
  .hero h1,.article h1{font-size:34px}
  .article h2{font-size:28px}
  .article{padding:24px}
}