According to the specs, the lovely Astrophy should line the top of the blue box, and should spill outside the box to the left and right. That is to say, there should be many cats in a horizontal line touching either side of the canvas/viewport, and the cats should be vertically aligned to be between the HTML box's blue border and the BODY box's green border. Note that there should be one Astrophy EXACTLY horizontally centred across the viewport, so its left paw (the one that is to our right) should be EXACTLY above the bathroom tile that appears at the top of the inner BODY box.
ASTROPHY SHOULD NOT BE CLIPPED BY THE HTML BOX'S BORDERS!