RoboHelp 2015 styles not appearing in generated output

Hi

I have imported  a FM book into RH2015 and mapped FM styles to HTML styles. The text is correctly styled in the RH editor window, but when I generate WebHelp (both varieties), the output is not styled accordingly.

When I look at the raw HTML, I can see that the text in question is wrapped correctly. For example, <spanclass="FM_bold">Status</span> ) is in the code, but the wrapped text does not get bolded. It seems as if the CSS is not being read, even though it is correctly referenced in the meta-tags.

Any help?

Thanks

Geoffrey Marnell