This option in the footer allows you to quickly change the current font size. The plus sign ('+') stands here to increase the font, the minus sign ('-') stands thereby for the reduction of the font size. The button ('*') sets the font size to the default setting. From the menu of the extended tool tips (moving the mouse over a button) a specific font size can be set directly. In addition, the currently set font size is displayed in the extended tooltips.

Another way to change the font size is to pass a 'fontsize' URL/Get - parameter with a value in the range of '0.5' to '1.5' to any page.

For example:

https://certus.in/?fontsize=0.5

Or:

https://certus.in/site/pages/cia-en/news-en.cia?p=10&fontsize=1.5