Site gone weird!

HEEEELP!

Earlier today I copied the Twenty Fourteen functions.php file to my Twenty Fourteen child theme, with the intention of modifying the font. However, the site went down, and on checking with my host Support I was told that copying an exact replica of the functions.php file from the parent to the child theme stops the site from functioning.

I subsequently deleted the functions.php file from the child theme, and the site was downloadable, BUT it’s now messed up. It looks like a badly designed mobile view, or something.

I’ve tried restoring my files to yesterday, and also tried reinstalling Twenty Fourteen, but the problem remains.

If anyone can assist, would be VERY grateful.

My site is https://www.boomtownrap.com

Cheers
Ross