:root { color-scheme: light dark; --brand: #2d7ef7; }
* { box-sizing: border-box; }
body { margin: 0; font-family: system-ui, sans-serif; background: #0f1216; color: #e8eef5;
       min-height: 100vh; display: flex; flex-direction: column; }
.center { flex: 1; display: flex; align-items: center; justify-content: center; }
.card { background: #1a1f28; padding: 28px; border-radius: 12px; width: 320px;
        box-shadow: 0 10px 40px rgba(0,0,0,.4); }
.card h1 { font-size: 1.1rem; margin: 0 0 16px; }
label { display: block; font-size: .85rem; margin: 12px 0 4px; opacity: .8; }
input { width: 100%; padding: 10px; border-radius: 8px; border: 1px solid #2c3442;
        background: #0f1216; color: inherit; font-size: 1rem; }
button { width: 100%; margin-top: 18px; padding: 11px; border: none; border-radius: 8px;
         background: var(--brand); color: #fff; font-weight: 600; font-size: 1rem; cursor: pointer; }
button:disabled { opacity: .6; cursor: progress; }
.err { color: #e23b4e; font-size: .85rem; min-height: 1.2em; margin-top: 10px; }
.topbar { display: flex; justify-content: space-between; align-items: center;
          padding: 14px 20px; background: #1a1f28; }
.topbar button { width: auto; margin: 0; padding: 8px 14px; background: #2c3442; }