Something new simply gets stacked on top and all other elements move down. You can't think that way. You must see the page as a whole. When an element is added to the page, the design must incorporate that element. Don't simply add.
Printing is the biggest.
Now, you may say that no one would want to print any of these pages. That may be, but even so, you have text in a myriad of colors from page to page, and if a print did occur, the page would print with a white background and oddly colored text. I'm not telling you to get rid of the black background, but think it through a bit. If no one ever prints, then maybe you're good to go. If they do, there may be problems.