body {
    font-family: Arial, sans-serif;
    background-color: #f9f9f9;
    margin: 0;
    padding: 20px;
    line-height: 1.6;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background-color: #ffffff;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

h1, h2 {
    text-align: center;
    color: #333;
}

ul {
    list-style-type: none;
    padding: 0;
}

li {
    margin: 10px 0;
}

input[type="checkbox"] {
    margin-right: 10px;
}

button {
    background-color: #4CAF50;
    color: white;
    padding: 10px 15px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}

button:hover {
    background-color: #45a049;
}

.message {
    color: green;
    text-align: center;
    margin-bottom: 20px;
}

iframe {
    width: 100%;
    height: 600px;
    border: none;
}