All blocks are pink and black or red and black,

All blocks are pink and black or red and black, with the exception of bed blocks, chests, animal blocks, etc. Grass, trees, and stone all have this error.I'm trying to join a friend's realm from my PC and I'm getting this error, but I have no problem joining the same realm from my smartphone. This started after it asked me to download new files to join. Did something get installed incorrectly, and how do I fix it? Help!!