diff --git a/src/component/Display.css b/src/component/Display.css
index d3196e070..9b170e400 100644
--- a/src/component/Display.css
+++ b/src/component/Display.css
@@ -6,7 +6,9 @@
   flex: 0 0 auto;
   width: 100%;
 }
-
+@media screen and (min-width: 0px) and (max-width: 500px) {
+  .component-display  { background-color: red; }
+}
 .component-display > div {
   font-size: 2.5rem;
   padding: 0.2rem 0.7rem 0.1rem 0.5rem;