body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    text-align: center;
}

header {
    background-color: #4CAF50;
    color: white;
    padding: 1em 0;
}

main {
    padding: 2em;
}

button {
    padding: 0.5em 1em;
    font-size: 1em;
    cursor: pointer;
}

footer {
    background-color: #333;
    color: white;
    padding: 1em 0;
    position: fixed;
    width: 100%;
    bottom: 0;
}