Why is my screen rotated? (On the main page?)

Someone from Aperture Science told me something pretty big brain; You likely have more horizontal monitor space than vertical monitor space. Therefore, we can probably fit more on the screen if we utilise more of it. But I'm lazy, so that was the easiest way of doing it.

P.S. If you refresh the main page enough times, something may happen. There are 7 different things that can happen, so good luck!