.fa-facebook-square, .fa-linkedin{
font-size: 40px;
}
.fa-instagram:before {
    font-size: 40px;
}

.fa-linkedin {
    background: url('/sites/default/files/youtube_1.png') no-repeat center center;
    background-size: contain;
    width: 40px;
    height: 40px;
    display: inline-block;
    font-size: 40px;
}

.fa-linkedin:before {
    content: none !important;
}