body {
    background-color: #0d0d0d;
    color: #00ff00;
    font-family: 'Courier New', monospace;
    text-align: center;
    margin: 0;
    padding: 0;
}

h1 {
    margin-top: 20px;
}

.challenge-list {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-top: 30px;
}

.challenge-button, .back-button {
    background-color: #003300;
    color: #00ff00;
    padding: 15px;
    margin: 10px;
    text-decoration: none;
    font-size: 18px;
    border-radius: 5px;
    width: 250px;
    text-align: center;
    display: inline-block;
}

.challenge-button:hover, .back-button:hover {
    background-color: #005500;
}