Variable: face-remapping-alist

Alist of face remappings.
Each element is of the form:

(FACE . REPLACEMENT),

which causes display of the face FACE to use REPLACEMENT instead.
REPLACEMENT is a face specification, i.e. one of the following:

(1) a face name
(2) a property list of attribute/value pairs, or
(3) a list in which each element has the form of (1) or (2).

List values for REPLACEMENT are merged to form the final face
specification, with earlier entries taking precedence, in the same as
as in the `face' text property.

Face-name remapping cycles are suppressed; recursive references use
the underlying face instead of the remapped face. So a remapping of
the form:

(FACE EXTRA-FACE... FACE)

or:

(FACE (FACE-ATTR VAL ...) FACE)

causes EXTRA-FACE... or (FACE-ATTR VAL ...) to be _merged_ with the
existing definition of FACE. Note that this isn't necessary for the
default face, since every face inherits from the default face.

If this variable is made buffer-local, the face remapping takes effect
only in that buffer. For instance, the mode my-mode could define a
face `my-mode-default', and then in the mode setup function, do:

(set (make-local-variable 'face-remapping-alist)
'((default my-mode-default)))).

Because Emacs normally only redraws screen areas when the underlying buffer contents change, you may need to call `redraw-display' after changing this variable for it to take effect.