ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    background-color: #f1f1f1;
    
}

li a {
    display: block;
    color: #000;
    padding: 8px 16px;
    text-decoration: none;
}

/* Change the link color on hover */
li a:hover {
    background-color: #555;
    color: white;
    text-decoration: none;
}

.list-group.panel > .list-group-item {
    border-bottom-right-radius: 4px;
    border-bottom-left-radius: 4px
}
.list-group-submenu {
    margin-left:20px;
}