:root{
  --bg:#f5f8fb;
  --surface:#ffffff;
  --text:#1d2b36;
  --muted:#5b6b78;
  --line:#d9e4ec;
  --primary:#0d4f8b;
  --primary-2:#3aa9cf;
  --secondary:#3f8f7d;
  --dark:#24333b;
  --accent-gradient:linear-gradient(135deg,var(--primary) 0%, var(--primary-2) 58%, var(--secondary) 100%);
  --shadow:0 16px 40px rgba(18, 42, 66, 0.10);
  --radius:18px;
  --max:960px;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family: "Segoe UI", Arial, Helvetica, sans-serif;
  color:var(--text);
  background:
    radial-gradient(circle at top right, rgba(58,169,207,.15), transparent 28%),
    radial-gradient(circle at bottom left, rgba(63,143,125,.10), transparent 24%),
    var(--bg);
  line-height:1.65;
}
a{color:var(--primary); text-decoration:none}
a:hover{text-decoration:underline}
.hero{
  background:var(--accent-gradient);
  color:#fff;
  padding:56px 24px 72px;
  position:relative;
  overflow:hidden;
}
.hero::after{
  content:"";
  position:absolute;
  inset:auto -120px -120px auto;
  width:360px;
  height:360px;
  border-radius:50%;
  background:rgba(255,255,255,.08);
  filter:blur(2px);
}
.wrap{
  width:min(var(--max), calc(100% - 32px));
  margin:0 auto;
}
.brand{
  font-size:14px;
  letter-spacing:.12em;
  text-transform:uppercase;
  opacity:.9;
  margin-bottom:16px;
  font-weight:600;
}
h1{
  margin:0;
  font-size:clamp(2rem,4vw,3rem);
  line-height:1.12;
}
.subtitle{
  margin:14px 0 0;
  max-width:760px;
  font-size:1.05rem;
  opacity:.96;
}
.meta{
  margin-top:18px;
  font-size:.95rem;
  opacity:.9;
}
.main{
  margin-top:-34px;
  padding:0 0 56px;
}
.card{
  background:var(--surface);
  border:1px solid rgba(13,79,139,.08);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
  padding:28px;
}
.toc{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(180px,1fr));
  gap:10px 16px;
  margin:0;
  padding:0;
  list-style:none;
}
.toc a{
  display:block;
  padding:10px 12px;
  border:1px solid var(--line);
  border-radius:12px;
  background:#fbfdff;
}
.section{
  margin-top:22px;
}
.section h2{
  margin:0 0 10px;
  font-size:1.45rem;
  color:var(--primary);
}
.section h3{
  margin:18px 0 8px;
  font-size:1.02rem;
  color:var(--dark);
}
.section p, .section li{
  color:var(--text);
}
.section ul{
  margin:10px 0 0 20px;
  padding:0;
}
.note{
  margin-top:18px;
  padding:14px 16px;
  border-left:4px solid var(--secondary);
  background:rgba(63,143,125,.08);
  border-radius:10px;
}
.footer{
  margin:30px 0 0;
  padding-top:18px;
  border-top:1px solid var(--line);
  color:var(--muted);
  font-size:.95rem;
}
.topbar{
  display:flex;
  gap:12px;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  margin-bottom:22px;
}
.badge{
  display:inline-flex;
  align-items:center;
  gap:8px;
  border:1px solid rgba(255,255,255,.22);
  border-radius:999px;
  padding:8px 12px;
  font-size:.9rem;
  background:rgba(255,255,255,.08);
}
.navlinks{
  display:flex;
  flex-wrap:wrap;
  gap:12px;
}
.navlinks a{
  color:#fff;
  font-weight:600;
  opacity:.96;
}
.small{
  font-size:.95rem;
  color:var(--muted);
}
@media (max-width:640px){
  .hero{padding-top:40px;padding-bottom:58px}
  .card{padding:22px}
  .topbar{align-items:flex-start}
}