Originally Posted by Iceblossom

Another way to easily change font sizes is to hold down control and then use the wheel in the middle of your mouse (if it has one and most do).

I have vision issues and a large screen and most websites I use around 110-130% size.

For light on dark text (which I have particular problems with) you can usually click and drag/highlight the area you need to see better. I used to use that a lot back in the early days of the net when a lot of websites had type was that acid green or bright blue on black.