body, h1, p, ul {
    margin: 0;
    padding: 0;
}

body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f9;
    color: #333;
    line-height: 1.6;
    text-align: center;
    padding: 20px;
}

header {
    background: #4a90e2;
    color: #fff;
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 20px;
}

header h1 {
    margin-bottom: 10px;
}

header ul {
    list-style-type: disc;
    margin: 10px 0 0 20px;
    text-align: left;
    display: inline-block;
}


header li {
    margin: 5px 0;
}

main div {
    background: #fff;
    padding: 20px;
    margin: 0 auto;
    max-width: 500px;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

main h1 {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

input[type="text"] {
    padding: 8px;
    width: 150px;
    margin: 10px 0;
    border: 2px solid #ddd;
    border-radius: 5px;
    font-size: 1rem;
    text-align: center;
}

button {
    padding: 8px 15px;
    margin: 5px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    background: #4a90e2;
    color: #fff;
    font-size: 1rem;
    transition: background 0.3s;
}

button:hover {
    background: #357abd;
}

#nextLevel {
    background: #28a745;
    cursor: pointer;
}

#nextLevel:hover {
    background: #1e7e34;
}

#nextLevel:disabled {
    background: #ccc;
    color: #666;
    cursor: not-allowed;
    box-shadow: none;
}

#nextLevel:hover {
    background: #1e7e34;
}

footer {
    margin-top: 30px;
    color: #777;
    font-size: 0.9rem;
}