:root{color-scheme:dark;font-family:system-ui,-apple-system,"Yu Gothic",Meiryo,sans-serif;background:#111820;color:#f0f5f7}*{box-sizing:border-box}body{margin:0;min-height:100vh;display:flex;flex-direction:column}a{color:#8ce9cf}header,footer{display:flex;align-items:center;gap:1.5rem;padding:1.2rem max(1.5rem,calc((100vw - 860px)/2));background:#17232b}header{justify-content:space-between;border-bottom:1px solid #2b3b44}.brand{text-decoration:none;font-weight:800;font-size:1.2rem;color:#f0f5f7}nav{display:flex;gap:1rem;flex-wrap:wrap}main{width:min(860px,calc(100% - 3rem));margin:3rem auto 5rem;flex:1}.eyebrow{color:#8ce9cf;font-weight:700;letter-spacing:.08em}h1{font-size:clamp(2.3rem,7vw,4rem);line-height:1.2;margin:.5rem 0 1.5rem}.lead{font-size:1.18rem;line-height:1.9;color:#d6e2e7;max-width:72ch}section{margin-top:2.5rem;padding-top:1.5rem;border-top:1px solid #33434b}h2{font-size:1.3rem}p{line-height:1.9}footer{flex-wrap:wrap;font-size:.9rem;color:#a9bbc4}code{font-size:.93em;background:#25333b;padding:.15em .3em;border-radius:.25em}@media(max-width:600px){header{align-items:flex-start;flex-direction:column}main{margin-top:2rem}}