This exercise asked me to create rules for the body, h1, h2 and p selectors and put them in an external stylesheet (mystyle1.css). I made the background color #EAEAEA, the h1 color green and the h2 color maroon. formatting commands for the p selector enabled me to set the font as Georgia by preference and Times New Roman or a serif font as alternatives.
I also stipulated a size for h3, to make it fit in with the text font and size.
For this exercise I have specified the font size for headings as percentages of the basic p size.
Note that specifying the p in a different font (Georgia or a serif one) makes the listing appear in a contrasting font (the body font: Verdana or sans-serif).