:root { --font: system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif; }
* { box-sizing: border-box; }
body { font-family: var(--font); margin: 2rem auto; max-width: 720px; padding: 0 1rem; line-height: 1.55; }
h1,h2,h3 { line-height: 1.2; margin: 0 0 .5rem; }
p { margin: .5rem 0; }
ul { margin: .5rem 0; padding-left: 1rem; }
li { margin: .25rem 0; }
a { color: inherit; text-decoration: underline; }
nav ul { list-style: none; padding: 0; display: flex; gap: .75rem; margin: 0 0 1rem; }
footer { margin-top: 2rem; font-size: .9rem; opacity: .8; }
hr { border: 0; border-top: 1px solid #ddd; margin: 1rem 0; }