diff --git a/core/themes/seven/jquery.ui.theme.css b/core/themes/seven/jquery.ui.theme.css
index 89aa38b..0ff1542 100644
--- a/core/themes/seven/jquery.ui.theme.css
+++ b/core/themes/seven/jquery.ui.theme.css
@@ -323,6 +323,15 @@
 }
 
 /**
+ * Overlays
+ */
+.ui-widget-overlay {
+  background: #000;
+  opacity: .70;
+  filter: Alpha(Opacity=70);
+}
+
+/**
  * Slider
  */
 .ui-slider {