body { font-family: system-ui, sans-serif; margin: 0; background: #f6f7f9; color: #1c2430; }
main { max-width: 26rem; margin: 6rem auto; padding: 2rem; background: #fff; border-radius: 8px;
       box-shadow: 0 1px 4px rgba(0, 0, 0, .12); }
h1 { font-size: 1.25rem; margin-top: 0; }
label { display: block; margin-top: 1rem; font-size: .875rem; }
input { width: 100%; padding: .5rem; margin-top: .25rem; box-sizing: border-box; font-size: 1rem; }
button { margin-top: 1.5rem; padding: .6rem 1.2rem; cursor: pointer; font-size: 1rem; }
.error { color: #b00020; margin-top: 1rem; }
@media (max-width: 30rem) { main { margin: 1rem; padding: 1.25rem; } }