alexmv

I think you need to create better box hierarchy. You need one container (div or span) for the gray boxes and another container for the text box.
 
Centering text in box is simple as: text-align:center;
 
One good idea when asking for help is to use online front-end playground like codepen.io. Instead of making screenshots, you can show the problem with code and receive an answer with code.
 
You can also try some front-end framework like Bootstrap. It can make the things a lot easier. The downside is that you need to learn how to use it first.
 
Alex