I overlooked your statement that you're designing a responsive project and this is why your text is different. Responsive projects, unlike standard Captivate projects, don't convert text to images. When you publish the text actually stays as live text and it depends upon HTML and CSS for any special styling.
Unfortunately, this isn't a simple thing to modify. I've spent a bit of time figuring out how to get the HTML5 file to style all the text to a specific web font, but I'm not specifying anything beyond all the text display as a set font and every project I create, which works in my circumstances, uses that web font in each project.