diff --git a/.env.example b/.env.example
index aa4bd857a..66d51d9b1 100644
--- a/.env.example
+++ b/.env.example
@@ -56,6 +56,7 @@ MIX_API_SEARCH="${API_SEARCH}"
 
 ACTIVITYPUB_INBOX=false
 ACTIVITYPUB_SHAREDINBOX=false
+HORIZON_DARKMODE=true
 
 # Set these both "true" to enable federation.
 # You might need to also run: