body {
    font-family: sans-serif;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    background-color: #f0f0f0;
}

header {
    background-color: #333;
    color: white;
    text-align: center;
    padding: 1em 0;
}

main {
    padding: 20px;
    text-align: center;
    flex: 1;
}

button {
    padding: 10px 20px;
    background-color: #007bff;
    color: white;
    border: none;
    cursor: pointer;
}

footer {
    background-color: #333;
    color: white;
    text-align: center;
    padding: 0.5em 0;
}