body {
    font-family: Arial, sans-serif;
    background-color: #f8f9fa;
    margin: 0;
    padding: 0;
}

.container {
    width: 80%;
    margin: auto;
    overflow: hidden;
}

h1 {
    color: #333;
    text-align: center;
    margin-top: 50px;
}

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

.list-group-item {
    background-color: #fff;
    border: 1px solid #ddd;
    padding: 10px;
    margin-bottom: 5px;
}

.list-group-item a {
    text-decoration: none;
    color: #007bff;
}

.folder {
    cursor: pointer;
    margin: 5px 0;
}

.folder::before {
    content: "📁";
    margin-right: 5px;
}

.file::before {
    content: "📄";
    margin-right: 5px;
}

.nested {
    display: none;
    margin-left: 20px;
}

.active .nested {
    display: block;
}