diff --git a/src/scss/thumbnail.scss b/src/scss/thumbnail.scss
index d851b148..14795b33 100644
--- a/src/scss/thumbnail.scss
+++ b/src/scss/thumbnail.scss
@@ -14,12 +14,12 @@
 
 :host([details]) {
   border: 1px solid var(--primary-color);
-  border-radius: 5px;
+  border-radius: var(--ha-card-border-radius, 4px);
   padding: 2px;
 }
 
 img {
-  border-radius: 5px;
+  border-radius: var(--ha-card-border-radius, 4px);
 
   // Not 'contain' as some thumbnails may vary in aspect-ratio slightly and
   // should be clipped to fill the thumbnail div whilst maintaining