there are 2 kinds of bad:
The first, we can't help with: Lousy style taste just can't be overcome
The second: Coding, we (and Sigil) can help.
a) Validate the CSS (right-click the CSS file: Validate with W3C)
b) test with ADE (and NOT Calibre) and the device targeted
c) Read the Know
issues wit ADE Sticky in the EPUB forum