I'd like to adjust the background colour of the part of the diffs displayed by Magit. In particular, the background colour of the text
3rd in the image. I'd like to increase the contrast between the background of the unchanged section and the changed section.
What is the correct setting to customize?
Also, when I recently restarted emacs, it started showing the mode-line and section headers in a very small font (as shown). How do I change these font sizes to be the same as the regular text?
Emacs version: GNU Emacs 24.3.1 (x86_64-redhat-linux-gnu, GTK+ Version 3.22.10) of 2017-09-12 on x86-017.build.eng.bos.redhat.com
Magit version: Some version from five years ago.