.header {
    min-height:300px;
    background:url("../backgrounds/BLOCKS.png") center top / cover no-repeat fixed rgb(255, 255, 255);
}
h1.heading3 {
    text-align: center;
}
@media only screen and (min-width : 768px) {
    .header {
        min-height: 142px;
    }
}
@media only screen and (min-width : 1024px) {
    .header {
        min-height: 142px;
    }
}