diff --git a/users/crumb/programs/emacs/modules/syd-ui.el b/users/crumb/programs/emacs/modules/syd-ui.el
index 4478f45..8c95896 100644
--- a/users/crumb/programs/emacs/modules/syd-ui.el
+++ b/users/crumb/programs/emacs/modules/syd-ui.el
@@ -5,4 +5,9 @@
   :config
   (load-theme 'kanagawa-wave t))
 
+;; Display (relative) line numbers only in prog-mode derivatives.
+(use-package emacs
+  :hook ((prog-mode-hook . display-line-numbers-mode))
+  :custom (display-line-numbers-type 'relative))
+
 (provide 'syd-ui)