Google Introduces "Gmail Blue" : It’s Gmail, only bluer.

Another product of Google? An update for Gmail? Or another feature?
The answer is 'No'.

Gmail Blue is actually an April Fool's Day prank of Google, where everything on their email service are blue
As posted on a YouTube video, it took them 6 years to develop the technology to achieve Gmail Blue.

You click on COMPOSE.
Compose, the button blue.
The word itself – Blue.
Bold face is blue.
Underline, is blue.
Italics is blue as well.
You write in the body of the email, the font comes up blue, you don’t have to make it Blue, it is Blue. It just is Blue.
The little lines, they’re in blue.
When you go into help it’s blue.
It’s Gmail, only bluer.

Check out the video below:

Is there a hidden meaning behind this video? Is Google hitting Facebook because Facebook is very well known on its blue color? Or it is just a simple April Fool's Day prank of Google?
Imagine if Gmail transformed into Gmail Blue, crazy!