It is Azure.
As to creating templates as they are known in the current version of RoboHelp, if you mean from scratch, then I think the answer is negative. I think I have only seen one claim from someone really creating their own and unsurprisingly I learned that because they were on the forum with problems.
Editing a supplied template for use in RoboHelp is a different thing. You can open an output and then use your browsers developer tools to find out how it is defined in the CSS. Then you can override what is not available in the editor defining it in a file called user.css that you add in the editor under layout > user assets.
How well that would work from Fm I couldn't say. My instincts are screaming not to consider it.
I think @Jeff_Coatsworth has given you good advice saying go from Fm to Rh. Then you could go frameless with many more editing options. Context sensitive calls using URLs will be different. That's covered on my site.
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My site www.grainge.org includes many free Authoring and RoboHelp resources that may be of help.