body {
    font-family: Arial, sans-serif;
    margin: 20px;
}

.folder {
    cursor: pointer;
    display: flex;
    align-items: center;
    margin-bottom: 5px;
}

.folder img {
    width: 20px;
    margin-right: 10px;
}

.folder-items {
    display: none;
    margin-left: 30px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
}

.folder-items.open {
    display: block;
    max-height: 500px;
}

.folder-items a {
    text-decoration: none;
    color: blue;
    margin-bottom: 5px;
    display: inline-block;
}

.folder-items a:hover {
    text-decoration: underline;
}