diff --git a/apps/machine/src/composables/useTheme.ts b/apps/machine/src/composables/useTheme.ts
index 48c6444..edcbfa0 100644
--- a/apps/machine/src/composables/useTheme.ts
+++ b/apps/machine/src/composables/useTheme.ts
@@ -23,6 +23,8 @@ const MODE_KEY = 'lamassu-color-mode'
 const current = ref<ThemeId>(loadTheme())
 const colorMode = ref<ColorMode>(loadColorMode())
 
+const isElectron = !!(window as Record<string, unknown>).electronAPI
+
 function loadTheme(): ThemeId {
   try {
     const stored = localStorage.getItem(THEME_KEY)
@@ -32,7 +34,7 @@ function loadTheme(): ThemeId {
   } catch {
     // localStorage unavailable (e.g. SSR)
   }
-  return 'gruvbox'
+  return isElectron ? 'catppuccin' : 'gruvbox'
 }
 
 function loadColorMode(): ColorMode {
@@ -44,7 +46,7 @@ function loadColorMode(): ColorMode {
   } catch {
     // localStorage unavailable
   }
-  return 'dark'
+  return isElectron ? 'light' : 'dark'
 }
 
 function applyTheme(id: ThemeId) {
diff --git a/apps/machine/src/views/IdleView.vue b/apps/machine/src/views/IdleView.vue
index 877bd6a..2bc3a7b 100644
--- a/apps/machine/src/views/IdleView.vue
+++ b/apps/machine/src/views/IdleView.vue
@@ -197,9 +197,9 @@ function handleCashOut() {
       </div>
     </div>
 
-    <!-- Debug toggle (only visible when debug bar is hidden) -->
+    <!-- Debug toggle (only visible when debug bar is hidden, never in production) -->
     <Button
-      v-if="!atmStore.debugMode"
+      v-if="!atmStore.debugMode && atmStore.allowMockFallback"
       variant="ghost"
       size="sm"
       class="absolute bottom-4 right-4 text-xs text-muted-foreground"