How can I put the variable colors to appear in the center? (see in the bellow picture)
Thank you!
Hi! Could you give us the code please? 
In general, you could accomplish that by setting the left and right margins to auto, but without the code I can’t really tell what the structure of your page is, what kind of element this is, and what you have tried so far. So in order to be able to give you more detailed advice, we’ll need to see your code (preferably all of it, in a CodePen/GitHub link)