it used to be DEMs were red and REPs were blue - that changed at some point (80’s/90’s, I forget)
Democrat Red — Republican Blue
Prior to 1992, most election maps referenced Republican in blue and Democrat in red. However, after 1992, the media determined that using red for Democrats might be editorially construed to suggest that Democrat politicians and policies were in line with those of Socialist Democrats, which, of course, they are.