Not seeing how to colorize file type .diff

I made a patch.diff file from SourceTree, which basically is a git diff of changes in a file.

When I look at it in PHPStorm, the file name in the Project window is maroon (red?), but the text in the file is just black and white.

I'm trying to find how to have it understand the diff contents (as a .diff file) like some text editors I use do (Notepad++ or TextMate).