36 CFR Part 1194 - Information and Communication Technology (ICT) Final Standards and Guidelines (with amendments issued through Jan. 2018)

402.4 Characters on Display Screens.

At least one mode of characters displayed on the screen shall be in a sans serif font. Where ICT does not provide a screen enlargement feature, characters shall be 3/16 inch (4.8 mm) high minimum based on the uppercase letter “I”. Characters shall contrast with their background with either light characters on a dark background or dark characters on a light background.