nav#left-nav{
    background-color: #000;
}
nav#left-nav .logo{
    text-align: center;
    padding: 16px;
    box-sizing: border-box;
}
nav#left-nav button, nav#left-nav .accordion-button{
    color: #fff !important;
}
nav#left-nav div.accordion .accordion-button:not(.collapsed):before{
    background-color: #fff;
}
nav#left-nav .list-group-item {
    background-color: rgba(255,255,255,0.2);
    color: #fff;
}

nav#left-nav a.accordion-button:after{
    display: none;
}