body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    text-align: center;
}

header {
    background: #333;
    color: white;
    padding: 20px;
}

main {
    display: flex;
    justify-content: space-around;
    padding: 20px;
}

#section-list, #preview {
    width: 45%;
    padding: 20px;
    background: white;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

button {
    margin: 20px;
    padding: 15px 30px;
    font-size: 18px;
    background: #28a745;
    color: white;
    border: none;
    cursor: pointer;
}

button:hover {
    background: #218838;
}