Looking at this a little more closely it seems like it is not just the font size that is different but the font also. I think what is happening is that IE is substituting the font specified in the output for a default font - probably Times New Roman. Why it is doing this I don't know.
Is this happening on all projects you generate? Try using one of the supplied dummy projects and see if you get the same results.
I can and have changed the title.
Is the help being generated on a Windows 7 or 8 machine? Rh10 was released before the final version of Windows 8. If done on Windows 8, can you install on a Windows 7 machine in trial mode to compare?
Please also respond re browser default font.
See www.grainge.org for RoboHelp and Authoring tips
1) Thanks, Peter, for the title change.
2) It's my understanding that the doc-writer did the generation on Win7.
3) How does one change the default font in Win8/MSIE10? I've found the 'gear icon' on the right hand side, but don't see anything there or in the system control panels that suggest "default font".
Fonts are set where they always have been. Internet Options > General Tab > Appearance > Fonts
See www.grainge.org for RoboHelp and Authoring tips
North America
Europe, Middle East and Africa
Asia Pacific