@import url("https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:wght@400;500;600;700&family=Noto+Serif+SC:wght@600;700&display=swap");
:root{
  --ink:#15202b;
  --ink-2:#243447;
  --muted:#5b6b7c;
  --line:#d9e2ec;
  --paper:#fff;
  --soft:#f4f7fa;
  --tint:#e8f1f8;
  --brand:#0b6e99;
  --brand-2:#0a4f73;
  --accent:#c45c26;
  --shadow:0 12px 36px rgba(21,32,43,.08);
  --font:"IBM Plex Sans","PingFang SC","Microsoft YaHei",sans-serif;
  --display:"Noto Serif SC","Songti SC",serif;
  --max:1080px;
}
*{box-sizing:border-box}
html,body{margin:0}
body{
  font-family:var(--font);
  color:var(--ink);
  background:
    linear-gradient(180deg,#eef4f8 0%, #f7fafc 220px, #fff 420px);
  line-height:1.7;
  font-size:17px;
}
img{max-width:100%;display:block}
a{color:var(--brand);text-underline-offset:.15em}
.wrap{width:min(100% - 2rem,var(--max));margin-inline:auto}
.site-header{
  position:sticky;top:0;z-index:30;
  background:rgba(255,255,255,.92);
  backdrop-filter:blur(12px);
  border-bottom:1px solid rgba(11,110,153,.1);
}
.header-inner{display:flex;align-items:center;justify-content:space-between;gap:1rem;min-height:68px}
.brand{display:flex;align-items:center;gap:.7rem;color:inherit;text-decoration:none}
.brand-mark{
  width:36px;height:36px;border-radius:10px;
  background:linear-gradient(145deg,#0b6e99,#083d57);
  color:#fff;display:grid;place-items:center;font-weight:700;font-size:.95rem;
  box-shadow:0 8px 18px rgba(11,110,153,.25);
}
.brand small{display:block;font-size:.7rem;letter-spacing:.06em;color:var(--muted);text-transform:uppercase}
.brand strong{font-size:1.05rem;letter-spacing:-.02em}
.nav{display:flex;flex-wrap:wrap;gap:.9rem 1.15rem;font-size:.92rem}
.nav a{color:var(--muted);text-decoration:none}
.nav a[aria-current="page"],.nav a:hover{color:var(--brand-2);font-weight:600}
.hero{
  padding:clamp(2.2rem,5vw,3.6rem) 0 1.6rem;
  display:grid;grid-template-columns:1.15fr .85fr;gap:2rem;align-items:end;
}
.kicker{
  display:inline-block;font-size:.78rem;font-weight:700;letter-spacing:.08em;
  text-transform:uppercase;color:var(--brand);background:var(--tint);
  padding:.35rem .7rem;border-radius:999px;margin-bottom:.9rem;
}
h1{
  font-family:var(--display);
  font-size:clamp(1.9rem,4.2vw,2.85rem);
  line-height:1.2;letter-spacing:-.02em;margin:0 0 .9rem;
}
.lead{color:var(--muted);font-size:1.05rem;max-width:42ch;margin:0 0 1.35rem}
.cta-row{display:flex;flex-wrap:wrap;gap:.7rem}
.btn{
  display:inline-flex;align-items:center;justify-content:center;
  min-height:46px;padding:.7rem 1.15rem;border-radius:10px;
  font-weight:650;text-decoration:none;border:1px solid transparent;
}
.btn-primary{background:var(--brand);color:#fff}
.btn-primary:hover{background:var(--brand-2)}
.btn-ghost{background:#fff;border-color:var(--line);color:var(--ink)}
.hero-panel{
  background:#fff;border:1px solid var(--line);border-radius:18px;
  padding:1.2rem 1.3rem;box-shadow:var(--shadow);
  animation:rise .7s ease both;
}
.hero-panel h2{font-size:1rem;margin:0 0 .7rem}
.hero-panel ol{margin:0;padding-left:1.15rem;color:var(--muted);font-size:.95rem}
.hero-panel li{margin:.35rem 0}
.section{padding:1.4rem 0 2.2rem}
.section h2{
  font-family:var(--display);font-size:clamp(1.35rem,2.4vw,1.75rem);
  margin:0 0 .75rem;letter-spacing:-.01em;
}
.section .intro{color:var(--muted);max-width:62ch;margin:0 0 1.2rem}
.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:1rem}
.grid-2{display:grid;grid-template-columns:1.1fr .9fr;gap:1.2rem}
.card{
  background:#fff;border:1px solid var(--line);border-radius:16px;
  padding:1.15rem 1.2rem;box-shadow:0 6px 20px rgba(21,32,43,.04);
}
.card h3{margin:0 0 .45rem;font-size:1.05rem}
.card p{margin:0;color:var(--muted);font-size:.95rem}
.card a.more{display:inline-block;margin-top:.75rem;font-weight:600;text-decoration:none}
.prose{max-width:720px}
.prose h2{margin-top:2rem}
.prose h3{margin:1.4rem 0 .5rem;font-size:1.1rem}
.prose p,.prose li{color:var(--ink-2)}
.prose ul,.prose ol{padding-left:1.2rem}
.prose li{margin:.35rem 0}
.callout{
  background:var(--soft);border-left:4px solid var(--brand);
  padding:1rem 1.1rem;border-radius:0 12px 12px 0;margin:1.2rem 0;
  color:var(--ink-2);
}
.meta{color:var(--muted);font-size:.88rem;margin-bottom:1rem}
.toc{background:#fff;border:1px solid var(--line);border-radius:14px;padding:1rem 1.15rem}
.toc a{display:block;padding:.25rem 0;text-decoration:none;color:var(--ink-2)}
.site-footer{
  margin-top:1rem;border-top:1px solid var(--line);
  background:var(--soft);padding:1.6rem 0 2.2rem;color:var(--muted);font-size:.9rem;
}
.footer-inner{display:grid;grid-template-columns:1.2fr 1fr;gap:1.2rem}
.footer-inner a{color:var(--ink-2);margin-right:.8rem;text-decoration:none}
@keyframes rise{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:none}}
@media (max-width:860px){
  .hero,.grid-3,.grid-2,.footer-inner{grid-template-columns:1fr}
  .nav{display:none}
}
@media (prefers-reduced-motion:reduce){.hero-panel{animation:none}}