.header {
    padding-top: 50px;
    padding-bottom: 50px;
    color: white;
    background:
        url('img/header-background.jpg') 50% -100px fixed,
        linear-gradient(to bottom, #F8F8F8 0%, #1C6990 100%);
    text-align: center;
}

.header img {
    height: 200px;
}

@media screen and (min-width: 48em) {
    .header img {
        width: 192px;
    }
}

.header {
    padding-top: 50px;
    padding-bottom: 50px;
    color: white;
    background:
        url('img/header-background.jpg') 50% -100px fixed,
        #4c748c;
    text-align: center;
}

.header img {
    height: 200px;
}

@media screen and (min-width: 48em) {
    .header img {
        width: 192px;
    }
}

Use mean color as fallback
Use mean color as fallback
