[CSS Course Question]

The only thing I see is you don't capitalize the D in the div centerDoc. 

Most of the times, my problems come from creating duplicates/moving the file in another folder, then the page I'm refreshing in the web browser is not the one where I make the changes in the code editor.

I say that because I see you have several documents with similar names opened in Sublime. 

[Certifications]

Good job!