Add Styles to Console Statements

I was recently checking out Google Plus because they implement some awesome effects. I opened the console and same the following message: WARNING! Using this console may allow attackers to impersonate you and steal your information using an attack called Self-XSS. Do not enter or paste code that you do not understand. I wasn't surprised to see that message but what I did notice was that the text was red and the background was yellow. The text was even a bit bigger. How did they do it? Pretty easily: