My text is centering just fine but anything in a container doesn't center. Is there a way to make it so the boxes are aligned with the text automatically when I post?
well no...but a fluid element that is not the full width of it's parent that is also fluid is slightly more involved
Short story....yes you can.
(make note of your current settings changes before changing them , just grab a screen shot same as you did with the images above this time of your settings.)
if that video was halo 2 and not reach ...it might have shown me in a match where everyone is shooting sniper rifles that shoot out bouncy-sticky grenades while playing TeamDM on campaign maps
you can set those page widths to px instead of % as well, this way they will be static and the space on the sides of them will be fluid. just another option to have in the pocket