If you or your friend uses Google Chrome, this trick is just for you because it was written to work with Chrome. However, it is also possible to duplicate the trick on Opera and on Firefox little bit hard but if you follow my instructions then you can do. We will see how to do that, but first, let start with Chrome.
Trick for Google Chrome
First, open this location from C: drive which is depends on the operating system used by them.
open C:/Users/YourUsername/AppData/Local/Google/Chrome/User Data/Default/User StyleSheets
In windows for some security reason you can’t find AppData folder because its hidden so you have to check Show hidden folders option from Folder Option and then you can see AppData folder.
open ~/Library/Application Support/Google/Chrome/Default/User StyleSheets
open ~/.config/chromium/Default/User StyleSheets
In this folder you can see a file name Custom.css. Unfortunately this file will be empty(0 Byte in size). But you can open it in notepad so just open it in notepad by right click and click on edit.
Now i am giving you some CSS definitions which will do amazing changes in all web-sites visited by Chrome browser.
Just copy given code and paste it into that Custom.css file and Press Ctrl+S so it will saved in that original location with changes.
Click here for all codes.
If you have any kind of trouble contact me on facebook or by email.
Do this on your own risk.