diff --git a/nixos/desktop/package-configs/firefox/default.nix b/nixos/desktop/package-configs/firefox/default.nix
index f857706..5065913 100644
--- a/nixos/desktop/package-configs/firefox/default.nix
+++ b/nixos/desktop/package-configs/firefox/default.nix
@@ -28,6 +28,11 @@
       };
       ExtensionSettings = {
         # "*".installation_mode = "blocked"; # blocks all addons except the ones specified below
+        # Catppuccin Macchiato - Lavender theme:
+        "{15cb5e64-94bd-41aa-91cf-751bb1a84972}" = {
+          install_url = "https://addons.mozilla.org/firefox/downloads/latest/catppuccin-macchiato-lavender/latest.xpi";
+          installation_mode = "force_installed";
+        };
         # Sideberry:
         "{3c078156-979c-498b-8990-85f7987dd929}" = {
           install_url = "https://addons.mozilla.org/firefox/downloads/latest/sidebery/latest.xpi";