body::after {
    background-image: url(/images/proteins.png);
    opacity: 0.25;
    top:0;
    bottom:0;
    left: 0;
    right: 0;
    display: block;
    content: "";
    width: 100%;
    height: 100%;
    background-size: cover;
    background-attachment: fixed;
    background-position: center;
    position: absolute;
    z-index: -1;
}

.jumbotron {
    background-color: transparent;
}

body{
    background-color: transparent;
    position: relative;
}

.disabled {
    color: darkgrey;
    /*background-color: lightgrey;*/
}