:root{--n:#0b1530;--b:#2563eb;--t:#1f2937;--m:#6b7280;--bg:#f8fafc;--c:#fff;--l:#e5e7eb}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;font:17px/1.7 system-ui,-apple-system,Segoe UI,Roboto,sans-serif;color:var(--t);background:var(--bg)}
a{color:var(--b)}a:focus-visible,button:focus-visible,input:focus-visible{outline:3px solid #f59e0b;outline-offset:2px}
.w{max-width:1040px;margin:auto;padding:0 20px}.hd{background:var(--n);color:#fff}.hd .w{display:flex;flex-wrap:wrap;gap:14px;align-items:center;justify-content:space-between;padding:14px 20px}
.hd a{color:#fff;text-decoration:none}.logo{font-weight:800;letter-spacing:.04em}.logo span{color:#60a5fa}.hd nav a{margin-right:16px;font-size:15px}
.hero{background:linear-gradient(180deg,var(--n),#142350);color:#fff;padding:64px 0}.hero h1{font-size:clamp(30px,5vw,48px);line-height:1.15;margin:0 0 14px;max-width:760px}.hero p{max-width:640px;color:#cbd5e1}
.btn{display:inline-block;background:var(--b);color:#fff!important;padding:11px 20px;border-radius:8px;text-decoration:none;font-weight:600;border:0;cursor:pointer;font-size:16px}.btn.alt{background:#e0e7ff;color:var(--n)!important}
.grid{display:grid;gap:18px;grid-template-columns:repeat(auto-fit,minmax(260px,1fr))}.card{background:var(--c);border:1px solid var(--l);border-radius:12px;padding:20px}.card h3{margin:.2em 0}
main{padding:32px 0 56px}.bc{font-size:14px;color:var(--m);margin-bottom:14px}.meta{color:var(--m);font-size:14px}
article h2{margin-top:2em;font-size:26px}article table,.tw table{border-collapse:collapse;width:100%;background:#fff}th,td{border:1px solid var(--l);padding:8px 10px;text-align:left}th{background:#eef2ff}
.tbl{overflow-x:auto}.toc{background:#fff;border:1px solid var(--l);border-radius:10px;padding:14px 20px}.tip{background:#eff6ff;border-left:4px solid var(--b);padding:12px 16px;border-radius:6px;margin:18px 0}
.cta{background:var(--n);color:#fff;border-radius:12px;padding:22px;margin:28px 0}.cta p{color:#cbd5e1;margin:.3em 0 1em}.formula{background:#0f172a;color:#e2e8f0;padding:12px 16px;border-radius:8px;font-family:ui-monospace,monospace;overflow-x:auto}
label{display:block;font-weight:600;margin-top:12px}input{width:100%;padding:10px;border:1px solid #cbd5e1;border-radius:8px;font-size:16px}
.res{background:#fff;border:1px solid var(--l);border-radius:10px;padding:16px;margin-top:18px}.err{color:#b91c1c}.ft{background:var(--n);color:#cbd5e1;padding:32px 0;font-size:14px}.ft a{color:#fff;margin-right:14px}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}