diff --git a/lms/static/sass/shared/_modal.scss b/lms/static/sass/shared/_modal.scss
index ddf9621c1d..f6046153a4 100644
--- a/lms/static/sass/shared/_modal.scss
+++ b/lms/static/sass/shared/_modal.scss
@@ -1,6 +1,6 @@
 #lean_overlay {
     background: transparent;
-    @include background-image(radial-gradient(50% 30%, circle cover, rgba(0,0,0, 0.3), rgba(0,0,0, 0.8)));
+    @include background-image(radial-gradient(circle at 50% 30%, rgba(0,0,0, 0.3), rgba(0,0,0, 0.8)));
     display: none;
     height:100%;
     left: 0px;