Usually it’s the viewing configuration of your web browser that suddenly makes your fonts really BIG or really small.

Your computer mouse might have a scroll wheel (a small wheel between your left and right click buttons.) By default, many are programmed so that if you hold onto the control button and scroll up and down while browsing a website, it will change the viewing font. So try adjusting that first.

If that doesn't work, go into your web browser and change the viewing options. Usually that is under "VIEW" in the top menu of your web browser, then scroll down to Text Size or Text Zoom and alter the viewing size there.

I hope that helps!