:root{
  --navy:#101827;
  --blue:#2869f0;
  --blue-dark:#164fca;
  --ink:#172033;
  --muted:#65738a;
  --line:#dfe5ee;
  --soft:#f3f6fa;
  --paper:#fff;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--soft);color:var(--ink);font-family:Pretendard,-apple-system,BlinkMacSystemFont,"Segoe UI","Apple SD Gothic Neo",sans-serif;line-height:1.75;-webkit-font-smoothing:antialiased}
a{color:inherit}
.site-header{background:var(--navy);color:#fff}
.header-inner{width:min(920px,calc(100% - 40px));margin:auto;padding:17px 0;display:flex;align-items:center;justify-content:space-between;gap:16px}
.brand{display:flex;align-items:center;gap:10px;color:#fff;text-decoration:none;font-weight:850;letter-spacing:-.035em}
.brand-mark{display:grid;place-items:center;width:34px;height:34px;border-radius:11px;background:var(--blue);font-size:18px}
.home-link{color:#c7d3e5;text-decoration:none;font-size:14px;font-weight:750}
.home-link:hover{color:#fff}
.page{width:min(920px,calc(100% - 40px));margin:28px auto 64px}
.breadcrumb{margin:0 0 18px;color:#748198;font-size:13px}
.breadcrumb a{color:#41699f;text-decoration:none}
.hero{padding:34px;background:linear-gradient(145deg,#112039,#1b355a);color:#fff;border-radius:24px;box-shadow:0 18px 44px rgba(25,47,80,.14)}
.kicker{display:block;color:#9fc1ff;font-size:14px;font-weight:850}
.hero h1{margin:7px 0 12px;font-size:clamp(30px,5vw,44px);line-height:1.22;letter-spacing:-.05em}
.hero p{max-width:720px;margin:0;color:#c7d4e6;font-size:17px}
.article{margin-top:18px;padding:30px 34px;border:1px solid #e0e6ef;border-radius:22px;background:#fff;box-shadow:0 12px 36px rgba(31,51,82,.07)}
.article h2{margin:34px 0 10px;font-size:25px;line-height:1.35;letter-spacing:-.04em}
.article h2:first-child{margin-top:0}
.article h3{margin:25px 0 7px;font-size:19px;letter-spacing:-.025em}
.article p{margin:8px 0;color:#4f5d72;font-size:16px}
.article ul,.article ol{margin:10px 0;padding-left:23px;color:#4f5d72}
.article li{margin:7px 0}
.formula{margin:16px 0;border:1px solid #ccdcfa;border-radius:16px;background:#eef4ff;padding:20px;color:#173f7c;text-align:center;font-size:20px;font-weight:900;letter-spacing:-.025em}
.example{margin:16px 0;border-left:4px solid #2e70e9;border-radius:0 14px 14px 0;background:#f4f7fc;padding:17px 19px}
.example strong{color:#20324d}
.example>strong:first-child{display:block;margin-bottom:5px}
.checklist{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:15px 0}
.check{border:1px solid #e0e6ef;border-radius:15px;padding:16px;background:#fbfcfe}
.check strong{display:block;margin-bottom:5px}
.check p{margin:0;font-size:14px}
.data-table{width:100%;margin:16px 0;border-collapse:collapse;font-size:15px}
.data-table th,.data-table td{border-bottom:1px solid #e4e9f0;padding:11px 12px;text-align:left}
.data-table th{background:#f5f7fb;color:#44546b}
.data-table td:last-child,.data-table th:last-child{text-align:right}
.note{margin-top:18px;border-radius:14px;background:#fff8e8;color:#6b542c;padding:15px 17px;font-size:14px}
.cta{margin-top:18px;padding:24px;border-radius:20px;background:#eaf2ff;text-align:center}
.cta strong{display:block;color:#173f7c;font-size:20px}
.cta p{margin:5px 0 14px;color:#526b8f}
.cta a{display:inline-flex;border-radius:12px;background:var(--blue);color:#fff;text-decoration:none;padding:12px 18px;font-weight:850}
.cta a:hover{background:var(--blue-dark)}
.related{margin-top:34px}
.related h2{margin:0 0 12px;font-size:22px;letter-spacing:-.035em}
.related-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.related a{display:block;border:1px solid #dce4ef;border-radius:15px;background:#fff;padding:15px;text-decoration:none;font-weight:800}
.related a:hover{border-color:#9ebcf5;color:#1c5bc5}
.footer{padding:26px 20px 40px;text-align:center;color:#8390a2;font-size:12px}
.footer a{color:#5e6f88;font-weight:750}
.footer-contact{display:block;margin-top:7px}
@media(max-width:620px){
  .header-inner,.page{width:calc(100% - 24px)}
  .home-link{font-size:13px}
  .page{margin-top:18px}
  .hero{padding:25px 20px;border-radius:20px}
  .hero p{font-size:16px}
  .article{padding:23px 19px;border-radius:19px}
  .article h2{font-size:22px}
  .checklist,.related-grid{grid-template-columns:1fr}
  .formula{font-size:18px;padding:17px 12px}
  .data-table{font-size:13px}
  .data-table th,.data-table td{padding:9px 8px}
}