* { box-sizing: border-box; }
body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #f3f5f7;
    color: #1f2937;
}
.page {
    min-height: 100vh;
    display: grid;
    place-items: center;
    padding: 24px;
}
.card {
    width: min(620px, 100%);
    background: #fff;
    border: 1px solid #dfe3e8;
    border-radius: 16px;
    padding: 32px;
    box-shadow: 0 12px 30px rgba(0,0,0,.08);
}
.card h1 { margin-top: 0; }
.muted { color: #6b7280; }