diff --git a/src-ui/src/theme.scss b/src-ui/src/theme.scss
index bd32fc72f..cb752d3e8 100644
--- a/src-ui/src/theme.scss
+++ b/src-ui/src/theme.scss
@@ -15,6 +15,7 @@ body {
   --pngx-primary-darken-5: hsl(var(--pngx-primary), calc(var(--pngx-primary-lightness) - 5%));
   --pngx-primary-darken-15: hsl(var(--pngx-primary), calc(var(--pngx-primary-lightness) - 15%));
   --pngx-primary-darken-18: hsl(var(--pngx-primary), calc(var(--pngx-primary-lightness) - 18%));
+  --pngx-bg-alt: #fff;
   --pngx-bg-darker: var(--bs-gray-100);
   --pngx-focus-alpha: 0.3;
 }