Thanks for submitting a question about CSS files. What do you mean exactly by adding files to the front end? Is there a way we can replicate what you are experiencing? Is this a child theme you made yourself following the instructions in our child theme article?
Sorry for the problems with the BoldGrid UpTempo theme. I went ahead and tested this theme and found that everything is aligned the left to start with. I created a child theme and it appears to work okay. Please indicate what is shifting and we can investigate this further. At this point, everything looks to be operating normally.