body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
    margin: 0;
    padding: 20px;
    color: #333;
}

.container {
    width: 80%;
    margin: 0 auto;
    background-color: #fff;
    padding: 20px;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

.os-section {
    margin-bottom: 20px;
    padding: 20px;
    background-color: #e9e9e9;
    border-radius: 8px;
}

.os-section img {
    width: 50px;
    height: auto;
}

.dropdown-btn {
    padding: 10px;
    font-size: 16px;
    cursor: pointer;
    background-color: #0078d7;
    color: white;
    border: none;
    outline: none;
    width: 100%;
    text-align: left;
}

.dropdown-content {
    display: none;
    background-color: #f9f9f9;
    padding: 10px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

.dropdown-content a {
    display: block;
    padding: 8px 16px;
    text-decoration: none;
    color: #0078d7;
    cursor: pointer;
}

.dropdown-content a:hover {
    background-color: #f1f1f1;
}