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

.tree {
    list-style-type: none;
    padding-left: 20px;
}

.tree li {
    margin: 5px 0;
    position: relative;
}

.tree li::before {
    content: '';
    position: absolute;
    left: -10px;
    top: 0;
    bottom: 0;
    width: 1px;
    background: #ccc;
}

.tree li:last-child::before {
    display: none;
}

.tree li a {
    text-decoration: none;
    color: #333;
    padding: 5px 10px;
    border-radius: 4px;
    transition: background 0.3s;
}

.tree li a:hover {
    background: #e0e0e0;
}

.tree .icon {
    margin-right: 5px;
}

.tree .folder {
    font-weight: bold;
    color: #007bff;
}

.tree .file {
    color: #28a745;
}