How to increase or decrease the font size
in Mozilla Firefox, posted Oct 25th 2011
If you can’t read some tiny text on a website, or you mistakenly changed the browser font size, adjusting the font size is very helpful. There are a couple ways to do it.
The easiest way to increase the font size is to hold "Ctrl" then press the "+" or "-" key. Logically, the "+" key increases thezoom level while the "-" key decreases it. An alternative way to adjust the font size is to hold "Ctrl" and scroll the wheel up or down on your mouse to adjust the zoom; scroll it up to increase it, and down to decrease.
Pressing the "Ctrl" and "0" (zero) keys simultaneously will restore the default zoom level.