Ok. I need you to describe what exactly you modified and how (files, code, etc.) so that I could reproduce the issue. It would also help if you gave me your URL. You can PM it to me if you don't want to share it.
Zilan, I still need you to describe the way you modified CSS files because it is way too difficult to find out the issue you are reporting. The more information we have, the higher is the chance of getting a response shortly. Thanks for understanding.