:root{--bg:#ffffff;--fg:#1b1f23;--muted:#5b6470;--accent:#1f6feb}@media (prefers-color-scheme:dark){:root{--bg:#0d1117;--fg:#e6edf3;--muted:#9da7b3;--accent:#4493f8}}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--fg);font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;line-height:1.5}.container{max-width:960px;margin:0 auto;padding:2rem 1rem}.narrow{max-width:420px}.row{display:flex;align-items:center;justify-content:space-between;gap:1rem}.stack{display:grid;grid-gap:.75rem;gap:.75rem}button,input{font:inherit;padding:.6rem .8rem;border-radius:6px;border:1px solid var(--muted)}button{background:var(--accent);border-color:var(--accent);color:#fff;cursor:pointer}small{color:var(--muted)}