:root{color-scheme:light;--ink:#17202a;--muted:#52606d;--accent:#075985;--line:#d9e2e8;--bg:#f5f8fa}*{box-sizing:border-box}body{margin:0;color:var(--ink);background:var(--bg);font-family:-apple-system,BlinkMacSystemFont,"Hiragino Sans","Yu Gothic",sans-serif;line-height:1.75}header,footer{background:#fff;border-bottom:1px solid var(--line);padding:1rem max(1.25rem,calc((100% - 760px)/2))}footer{border-top:1px solid var(--line);border-bottom:0;margin-top:3rem}.brand{font-weight:700;text-decoration:none;color:var(--ink)}main{max-width:760px;margin:0 auto;padding:3rem 1.25rem}h1{font-size:clamp(1.8rem,5vw,2.6rem);line-height:1.35;margin:0 0 1rem}h2{font-size:1.3rem;margin-top:2.5rem}.lead{font-size:1.1rem;color:var(--muted)}a{color:var(--accent)}nav{display:flex;gap:1rem;flex-wrap:wrap}section{background:#fff;border:1px solid var(--line);border-radius:.5rem;padding:0 1.25rem 1rem;margin:1.25rem 0}