nav {
    position: relative;
    margin: 10px;
    width: 200px;
}

nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

nav ul li {
    /* Sub Menu */

}

nav ul li a {
    display: block;
    padding: 10px 15px;
    color: lightblue;
    text-decoration: none;
    -webkit-transition: 0.2s linear;
    -moz-transition: 0.2s linear;
    -ms-transition: 0.2s linear;
    -o-transition: 0.2s linear;
    transition: 0.2s linear;
}

nav ul li a:hover,
.nav-link-active {
    background: #1d4f71;
    color: #fff;
}

nav ul li a .fa {
    width: 16px;
    text-align: center;
    margin-right: 5px;
    float: right;
}

nav ul ul {
    background: rgba(0, 0, 0, 0.2);
}

nav ul li ul li a {

    border-left: 4px solid transparent;
    padding: 10px 20px;
}

nav ul li ul li a:hover,
.nav-link-active {
    border-left: 4px solid #3498db;
}

.sub-menu ul {
    display: none;
}

#sidebar,
.sub-menu {
    opacity: 0;
    transition: opacity 0.2s linear;
}