I've changed my diff-mode colours according to this article, but the character-based differences are shown in the original(?) and very bright colours, making them quite unreadable.
How do I change the colours that show the char-by-char differences on the removed/added lines?
With diff-refine faces:
(defun update-diff-refine-colors ()
"update the colors for diff faces"
(set-face-attribute 'diff-refine-added nil
:foreground "white" :background "darkgreen")
(set-face-attribute 'diff-refine-removed nil
:foreground "white" :background "darkred")
(set-face-attribute 'diff-refine-changed nil
:foreground "white" :background "darkblue"))
(eval-after-load "diff-mode"
'(update-diff-refine-colors))
There are more faces involved than the ones mentioned in the link you pointed to. The answer is to use C-u C-x = to find out what faces are involved. Those are the ones you need to customize.
Use M-x customize-face to customize the faces you are interested in. If you don't know which faces they are, put the cursor on that highlighted text and use C-u C-x =. Look near the bottom of *Help* for the face name.
From @djangoliv's answer it seems that these are the faces you need to customize: diff-refine-added, diff-refine-removed, diff-refine-changed.
So just M-x customize-face diff-refine-added and define the face as you like.
Do the same for diff-refine-removed and diff-refine-changed.
Easy, persistent, and the way Emacs wants to help you customize faces. See the Emacs manual, node Specific Customization.
