fix diff-mode face

emacs.el

@@ -634,10 +634,21 @@ drill-instructor.el"
 (add-hook 'diff-mode-hook
           (lambda ()
             (view-mode 1)
-            (set-face-foreground 'diff-file-header-face nil)
-            (set-face-foreground 'diff-header-face nil)
+            (let ((s 'diff-header))
+              (set-face-foreground s nil)
+              (set-face-background s nil)
+              (set-face-bold-p s t))
+            (let ((s 'diff-file-header))
+              (set-face-foreground s nil)
+              (set-face-background s nil)
+              (set-face-bold-p s t))
             (set-face-foreground 'diff-index-face "blue")
-            (set-face-foreground 'diff-hunk-header-face "cyan")
+            (let ((s 'diff-hunk-header))
+              (set-face-foreground s "cyan")
+              (set-face-bold-p s nil))
+            (let ((s 'diff-context))
+              ;; (set-face-foreground s "white")
+              (set-face-bold-p s t))
             (set-face-foreground 'diff-context-face nil)
             (set-face-foreground 'diff-removed-face "red")
             (set-face-foreground 'diff-added-face "green")