.header {
    background-image:linear-gradient( rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5) ), url("../images/bdonate2.jpg");
    background-repeat: no-repeat;
    background-attachment: fixed;
    height: 80vh;   
    width: 100%;
    position: relative;
    background-size: 100% 100%;

}