The
Koreader Project at Github has released a version with Kobo Glo HD support.
@Nick_1964; With Koreader, you can not only turn "Embedded Style" off, but under the "Set render style" menu there is a "clear all external styles" option. You can then select from the .css listed. You can also add your own .css, to apply your own settings, after what ever is already active. This is all doable on your device, no computer involved. Except the making of your own .css file, that you would want to do on a computer.
Luck;
Ken