.header:before {
    content: "";
    position: absolute;
    top: 0px;
    left: 0px;
    right: 0px;
    display: block;
    height: 20px;
    width: 100%;
    background-image: url(http://www.toowoombaregionalcouncil.com.au/tcof/wp-content/uploads/2018/01/bunting.png);
    background-repeat: repeat-x;
    background-size: 20px 20px;
    background-position: center top;
}