:root { color-scheme: dark; --bg:#0d1117; --fg:#c9d1d9; --dim:#8b949e;
        --blue:#58a6ff; --green:#3fb950; --edge:#21262d; }
* { box-sizing:border-box; }
body { margin:0; background:var(--bg); color:var(--fg);
       font:16px/1.65 system-ui,-apple-system,Segoe UI,sans-serif; }
nav { display:flex; gap:1.25rem; align-items:center; padding:.9rem 1.5rem;
      border-bottom:1px solid var(--edge); background:#01040980; }
nav strong { color:var(--blue); letter-spacing:.02em; }
nav a { color:var(--fg); text-decoration:none; padding:.25rem .6rem;
        border-radius:6px; }
nav a:hover { background:#21262d; color:#fff; }
main { max-width:44rem; margin:0 auto; padding:2.5rem 1.5rem 4rem; }
h1 { font-size:1.9rem; margin:0 0 .4rem; color:#fff; letter-spacing:-.01em; }
h2 { font-size:1.1rem; margin:2.2rem 0 .7rem; color:var(--blue);
     text-transform:uppercase; letter-spacing:.08em; }
.lead { font-size:1.1rem; color:var(--dim); margin:0 0 1rem; }
a { color:var(--blue); }
.checks { list-style:none; padding:0; margin:0; }
.checks li { padding:.5rem 0 .5rem 1.8rem; position:relative;
             border-bottom:1px solid #161b22; }
.checks li::before { content:"\2713"; position:absolute; left:0;
                     color:var(--green); font-weight:700; }
code { background:#161b22; padding:.12rem .4rem; border-radius:4px;
       color:#7ee787; font-size:.9em; }
pre { background:#010409; border:1px solid var(--edge); border-radius:8px;
      padding:.9rem 1rem; overflow:auto; color:#7ee787; font-size:.88rem; }
.clock { font-size:1.6rem; color:#fff; font-variant-numeric:tabular-nums;
         margin:.3rem 0; }
.foot { margin-top:2.5rem; padding-top:1.2rem; border-top:1px solid var(--edge);
        color:var(--dim); font-size:.88rem; }