Challenge 6 part 3

header {
    background-color: [some color];
    position: fixed; /* Makes the bar fixed */
    width: 100%; /* We want the bar to span the width of the window */
    z-index: 2; /* We want the bar to overlap the rest of the content, by default HTML elements have a z-index of 1 and this gives our header priority over default elements*/
    height: [some height]; /* Set a fixed height */
}