html, body {

    font-family: Arial, Helvetica, sans-serif;

    margin: 0;

}



header {

    background-color: #3498db;

    color: white;

    padding: 1rem;

    text-align: center;

    font-weight: bold;

    font-size: 3rem;

    margin-bottom: 3rem;

}



.container {

    width: 800px;

    margin: auto;

}