The sizes of the fonts used by the information center for the lettering in the masthead (the blue and black bars at the top of the screen) and in the footer (the black bar at the bottom of the screen) are fixed so that they do not overflow the space available.
The font sizes in the navigation panel (the panel on the left-hand side of the screen) and in the main panel are set using relative font sizes so that you can change them using browser functions. Be aware, however, that the space available for category headings in the navigation panel is fixed so using too large a font size may cause the category titles to be truncated.
The relative font sizes used by your browser can be controlled as follows: