diff --git a/.config/doom/config.el b/.config/doom/config.el
index 6395b2d..2669ed2 100644
--- a/.config/doom/config.el
+++ b/.config/doom/config.el
@@ -22,8 +22,19 @@
       doom-font (font-spec :family "monospace" :size 24 :weight 'semi-light)
       doom-variable-pitch-font (font-spec :family "sans" :size 24))
 
-; TODO how to treat sequencep as string? - theme toggle
-;(s-chop-suffixes '("-light" "-dark") doom-theme)
+(defun load-theme-string (theme)
+  (if (-contains? (custom-available-themes) (intern theme)) (load-theme (intern theme))))
+(defun toggle-theme (&optional suffix)
+  "Heuristically toggle between light and dark themes."
+  (interactive)
+  (let* ((theme (s-replace-all '(("light" . "dark") ("dark" . "light")
+                     ("black" . "white") ("white" . "black")
+                     ("day" . "night") ("night" . "day"))
+                   (symbol-name doom-theme)))
+        (theme-base (s-replace-regexp "-[^-]*$" "" theme)))
+    (or (if suffix (or (load-theme-string (concat theme "-" suffix)) (load-theme-string (concat theme-base "-" suffix)))) (load-theme-string (if (and (not suffix) (equal theme (symbol-name doom-theme))) (concat theme "-light") theme)) (load-theme-string theme-base))
+    )
+  )
 
 (setq display-line-numbers-type 'relative
       scroll-margin 6
diff --git a/.config/shell/graphical b/.config/shell/graphical
index a85bb0c..06acdf4 100644
--- a/.config/shell/graphical
+++ b/.config/shell/graphical
@@ -40,7 +40,8 @@ test "$XDG_CURRENT_DESKTOP" = "KDE" || return 0
 # Fix errors regarding broken mim database
 alias fixmime='sudo rm /usr/share/mime/packages/kde.xml && sudo update-mime-database /usr/share/mime'
 
-# Switch theme across KDE system and taskwarrior
+# Switch theme across system: KDE, Konsole, taskwarrior, bat
+# WIP: Emacs, Mozilla, diffr (git pager)
 theme_save="$XDG_CACHE_HOME/theme"
 #theme_default="$(d=$(date +%H) && test $d -gt 7 && test $d -lt 19 && echo light || echo dark)"
 theme_default="dark"
@@ -50,6 +51,9 @@ theme() {
 	then kcmshell5 kcm_lookandfeel
 	elif test "$theme" != "$THEME" -a "$2" != "q"
 	then kcmshell5 kcm_lookandfeel &
+		# TODO theme diffr
+		bak $XDG_CONFIG_HOME/git/diffr
+		emacsclient -e "(toggle-theme \"$theme\")"
 	fi
 	export THEME="$theme"
 	echo "$theme">"$theme_save"