:root{color-scheme:light dark;height:100%;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,Open Sans,Helvetica Neue,sans-serif}header{padding-block:3rem;ul{list-style-type:none;margin:0;padding:0;display:flex;gap:1rem}}footer{margin-top:auto;padding-block:3rem}body{height:100%;margin:40px auto;max-width:80ch;line-height:1.6;font-size:18px;padding:0 10px}h1,h2,h3{line-height:1.2}