See if this helps, it's from the section in the user's guide on changing fonts and colors within text files that are presented as stimuli:

See also: www.empirisoft.com/directrt/help/directrt_stim.htm

...you can embed style codes within a single text file for multiple font and colour formats. In the example below, different styles are used for the question wording (style 1), responses (style 2), and page footer (style 3). You can also place style codes in the middle of a line of text (e.g., to change the color or italics of a font). If you do use multiple style within a text file, DirectRT will use the first background colour it encounters (i.e., additional styles will not change the initial screen colour). Text files will always be located starting from the top left corner of the screen. Left and top margins are achieved with spaces and hard returns, respectively.