diff --git a/frontend/src/app/plugins/api.cljs b/frontend/src/app/plugins/api.cljs
index 2b65475c22..fc7d67968a 100644
--- a/frontend/src/app/plugins/api.cljs
+++ b/frontend/src/app/plugins/api.cljs
@@ -237,15 +237,7 @@
     :getTheme
     (fn []
       (let [theme (get-in @st/state [:profile :theme])]
-        (cond
-          (or (not theme) (= theme "system"))
-          (theme/get-system-theme)
-
-          (= theme "default")
-          "dark"
-
-          :else
-          theme)))
+        (theme/resolve-theme theme (theme/get-system-theme))))
 
     :getCurrentUser
     (fn []
diff --git a/frontend/src/app/plugins/events.cljs b/frontend/src/app/plugins/events.cljs
index a6078b2b2b..17e50140a1 100644
--- a/frontend/src/app/plugins/events.cljs
+++ b/frontend/src/app/plugins/events.cljs
@@ -53,16 +53,8 @@
 
 (defn- get-theme
   [state]
-  (let [theme (get-in state [:profile :theme])]
-    (cond
-      (or (not theme) (= theme "system"))
-      (theme/get-system-theme)
-
-      (= theme "default")
-      "dark"
-
-      :else
-      theme)))
+  (theme/resolve-theme (get-in state [:profile :theme])
+                       (theme/get-system-theme)))
 
 (defmethod handle-state-change "themechange"
   [_ _ old-val new-val _]
@@ -70,9 +62,7 @@
         new-theme (get-theme new-val)]
     (if (identical? old-theme new-theme)
       ::not-changed
-      (if (= new-theme "default")
-        "dark"
-        new-theme))))
+      new-theme)))
 
 (defmethod handle-state-change "shapechange"
   [_ plugin-id old-val new-val props]
diff --git a/frontend/src/app/util/theme.cljs b/frontend/src/app/util/theme.cljs
index 7291fe043e..07b21ec6cb 100644
--- a/frontend/src/app/util/theme.cljs
+++ b/frontend/src/app/util/theme.cljs
@@ -45,6 +45,17 @@
     (.removeAttribute node "class")
     (.add ^js (.-classList ^js node) class)))
 
+(defn resolve-theme
+  "Resolves the profile's theme setting to the effective UI theme ('dark' or
+  'light'): 'system' follows the given system theme, 'default' and an unset
+  theme mean dark, and any other value is taken as-is. Single source of truth
+  for the app's own theme and the theme reported to plugins."
+  [profile-theme system-theme]
+  (cond
+    (= profile-theme "system") system-theme
+    (= profile-theme "default") "dark"
+    :else (d/nilv profile-theme "dark")))
+
 (defn use-initialize
   [{profile-theme :theme}]
   (let [system-theme* (mf/use-state get-system-theme)
@@ -58,9 +69,5 @@
           (rx/dispose! s))))
 
     (mf/with-effect [system-theme profile-theme]
-      (set-color-scheme
-       (cond
-         (= profile-theme "system") system-theme
-         (= profile-theme "default") "dark"
-         :else (d/nilv profile-theme "dark")))
+      (set-color-scheme (resolve-theme profile-theme system-theme))
       (notify-color-scheme-listeners!))))