#header nav{
    padding-left: 4rem;
}

.btn-back {
    display: block;
    position: absolute;
    top:50%;
    transform: translateY(-50%);
    left: 0;
    width: 4rem;
    height: 4rem;
    overflow: hidden;
    text-indent: -1000px;
}

[lang=ar] .btn-back {
    left: unset;
    right: 0;
}

.btn-back::before{
    content: '⟪';
    display: block;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
    color: #333333;
    font-size: 2rem;
    text-indent: 0;
}