Know that the solution is quite simple, she guessed, if someone sadistica this question, it helped me the following:
I just ordered a container in which there were three of these block I need width and margin:auto;
The hierarchy it is > the main container with background then the container in which the > three blocks
there where three units I ordered first
similarly, the second, the third didn't touch
the width didn't ask each block separately, just ordered the main container footprint.
and began as it should, although maybe not quite korektno