:root{--bg:#fafafa;--fg:#1a1a1a;--muted:#555;--card:#fff;--line:#e2e2e2;--acc:#fe2c55}
@media (prefers-color-scheme:dark){:root{--bg:#121212;--fg:#eee;--muted:#aaa;--card:#1d1d1d;--line:#333}}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--fg);font:16px/1.6 system-ui,-apple-system,"Segoe UI",sans-serif}
main{max-width:680px;margin:0 auto;padding:40px 16px}
h1{font-size:1.6rem;margin:0 0 .25rem}
h2{font-size:1.1rem;margin-top:2rem}
.sub{color:var(--muted);margin-top:0}
a{color:var(--acc)}
nav{display:flex;gap:16px;flex-wrap:wrap;margin-top:2.5rem;padding-top:1rem;border-top:1px solid var(--line);font-size:.9rem}
.caja{background:var(--card);border:1px solid var(--line);border-radius:10px;padding:16px;margin:1rem 0}
code{display:block;word-break:break-all;font-size:.95rem;padding:10px;background:var(--bg);border-radius:6px}
button{margin-top:10px;padding:10px 16px;border:0;border-radius:8px;background:var(--acc);color:#fff;font-size:1rem;cursor:pointer}