body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    line-height: 1.6;
    background-color: #f4f4f4;
}

.illustration {
    text-align: center;
    margin-top: 20px;
}

.illustration img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
}

.container {
    max-width: 800px;
    margin: 50px auto;
    padding: 20px;
    border: 1px solid #ddd;
    background-color: #fff;
    border-radius: 8px;
}

h1, h2 {
    color: #333;
}

.task {
    margin-bottom: 30px;
}

.task h2 {
    margin-bottom: 10px;
}

.task p {
    margin-bottom: 10px;
}

pre {
    background-color: #eee;
    padding: 10px;
    border-radius: 5px;
    overflow-x: auto;
}

.navigation {
    text-align: center;
    margin-top: 20px;
}

.navigation a {
    padding: 10px 20px;
    text-decoration: none;
    color: #fff;
    background-color: #007bff;
    border-radius: 5px;
    margin: 0 10px;
}

.navigation a:hover {
    background-color: #0056b3;
}

.navigation a.disabled {
    background-color: #333;
    text-decoration: line-through;
}