Add command to toggle between dark and bright modes

configuration.org

@@ -1208,6 +1208,37 @@ Before this can be used, make sure the [[https://zhm.github.io/symbola/][Symbola
 (--set-emoji-font nil)
 #+END_SRC
 
+** Dark/bright mode
+
+#+begin_src emacs-lisp
+(defun gpolonkai/enable-dark-mode ()
+  "Turn on dark mode."
+  (load-theme 'tango-dark)
+  (set-face-background 'hl-line "gray25")
+  (set-face-background 'whitespace-line "orange4"))
+
+(defun gpolonkai/enable-bright-mode ()
+  "Turn on bright mode."
+  (load-theme 'tango)
+  (set-face-background 'hl-line "gray85")
+  (set-face-background 'whitespace-line "gold3"))
+
+(defcustom gpolonkai/dark-mode t
+  "Controls whether dark mode is enabled or not."
+  :type 'boolean
+  :group 'gpolonkai
+  :initialize #'custom-initialize-set)
+
+(defun gpolonkai/dark-mode (&optional enable)
+  "Toggles between dark and bright modes.
+If ENABLE is set, explicitly enable dark mode despite the current setting."
+  (interactive "p")
+  (setq gpolonkai/dark-mode (if enable t (not gpolonkai/dark-mode)))
+  (if gpolonkai/dark-mode
+      (gpolonkai/enable-dark-mode)
+    (gpolonkai/enable-bright-mode)))
+#+end_src
+
 * Set up global minor modes provided by Emacs
 
 ** Pretty lambdas