Have you checked if (a) the FM_Bold style is defined in your CSS & (b) is that CSS being applied to the output?
Thanks Jeff. Yes, the style is defined in the CSS, but it appears that the CSS referred to in the meta-tags is not being read when the page is rendered.
I eventually pointed all the topic sin my project to RHMapping.css and the changes I made to RHMapping.css were rendered in the browser. RHMapping.css seems to be overriding the CSS explicitly mentioned in the meta-tags (the CSS I was modifying without affect).
You can have 1 CSS applied to all topics of your output when you set up the Single Source Layout (SSL) recipe, but there was a bug in RH11 that caused the output topics to have 2 lines referring to 2 different CSS files (& the default one was applied 2nd, so it won out in the output's appearance). I don't have a copy of RH2015 to confirm that it's been fixed.