body { font-family: sans-serif; max-width: 800px; margin: 2rem auto; padding: 0 1rem; }
label { display: block; margin-top: 1rem; font-weight: bold; }
input { width: 100%; padding: 0.4rem; margin-top: 0.2rem; box-sizing: border-box; }
button { margin-top: 1rem; margin-right: 0.5rem; padding: 0.5rem 1rem; cursor: pointer; }
h3 { margin-top: 2rem; border-bottom: 1px solid #ccc; }