:root{color-scheme:light;--bg:#f7f8fa;--ink:#172332;--line:#d8dde4;--accent:#006a8a}:root[data-theme=dark]{color-scheme:dark;--bg:#12171f;--ink:#eff5fa;--line:#394453;--accent:#64dbf4}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.75 system-ui,sans-serif}header,main,footer{max-width:850px;margin:auto;padding:24px}header{display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line)}nav,footer{display:flex;gap:20px;flex-wrap:wrap}main{min-height:65vh;padding-block:48px}h1{font-size:clamp(30px,6vw,48px);line-height:1.15;letter-spacing:-.035em}p{margin:24px 0}a{color:var(--accent)}button,.cta{padding:12px;border:1px solid var(--line);background:transparent;border-radius:10px;color:var(--accent)}footer{font-size:14px;border-top:1px solid var(--line)}