body {
    font-family: Arial, sans-serif;
    background: #f5f5f5;
    margin: 0;
    padding: 0;
}
header {
    background: #222;
    padding: 20px;
    text-align: center;
}
header h1 {
    color: white;
    margin: 0;
}
.container {
    max-width: 800px;
    margin: 40px auto;
    background: white;
    padding: 20px;
    border-radius: 8px;
}
button {
    display: block;
    width: 100%;
    padding: 15px;
    margin: 10px 0;
    background: #0078ff;
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 18px;
    cursor: pointer;
}
button:hover {
    background: #005fcc;
}