Kyria has figured out how to post with different backgrounds and she can change the color when she wishes.
She does this with the <div> tag. If you do not know how to use the <div> tags a good HTML editor like Kompozer can easily show you how. Kyria often uses Kompozer to format her forum posts and let her change colors, etc.
Like if she wanted to change her Font to red she can. by doing this <font color="red">Like if she wanted to change her Font to red she can.</font>
She has never tried doing different fonts. But she assumes something like this should work. <div style="font-family: Arial Narrow;">She has never tried doing different fonts.</font></div>
but she assumes it can be done
you can go up and down in size easily with the <h1> through <h8> tags.
Of course someone has to have the same font you are using, otherwise it doesn't show up.
If you want to do a background like Kyria's this is the coding you would need to use. Feel free to change any aspect of it, put in your own picture, etc.
Please don't disallow the div tag, it's already bad enough that the horizontal rules and .svg images aren't allowed. Instead of ruining it for all of us proper HTML users, just get Kyria to stop doing the annoying background thing with her posts.