Interfering CSS Codes

Hi,
I have recently put in a CSS code for a jQuery feature on my forum.
I have added a sliding login bar and have inserted codes through CSS and templates.
I don't have a problem using the templates, because I am able to add html codes anywhere I want.
With the CSS stylesheet however, there is no defined structure, so when I insert a CSS code for a second feature, it interferes with the codes for my first feature, thus changing the formatting.
How can I make it so that the bits of CSS coding do not interfere/interact with each other?
Thanks alot.

it's most likely you have to remove the bottom } form you first code
then add the second code and be sure to have } after it.

can you post the two does as you have them now not working.