This tool allows you to edit the font.css file that defines how the text on your website looks. This uses CSS (Cascading Style Sheets), for more info here is a good Tutorial. If you are unsure about CSS you should not make more then one change at a time here, and be sure you know where and what the expected change is! To removed any element choose 'delete' from the pull down menu or type 'delete' in the field and it will be removed.