Working example:
http://calda.coffeecup.com/testpage.html

The C is a background image on the header, the text and rule are HTML elements and will resize according to the CSS rules set for them. This was a quick example, so it's not perfect. (View source to see the CSS/HTML)
You would need to adjust sizes, margins and paddings, and breakpoints to work with your site.

You are all *amazing*! Thanks for taking the time to help me! I'll be spending Monday playing in the RSD sandbox, and feel sure that, with what you guys have written (and DONE! Thanks, @paintbrush!) I can get this sorted.

Thank you!!!

Thank you for taking the time to put together that testpage -- it is so heartening to see that it *can* be done!

I viewed the source, but what would be most helpful of all is if you might post here or email me the .rsd file you created. Is that an option? I am still learning RSD, so seeing what I need to do *in the program* is the most beneficial thing for me....

Working on an RSD example now

OK, Elisabeth – file sent to your email.
Kept getting a "Forbidden" error when I tried attaching it (.zip) here.