[CORD-2324] Position the nodes not defined in the constraints

Change-Id: I712a90828e0b6a12b31f62f7391feee64c123f2c
diff --git a/src/index.scss b/src/index.scss
index 49a5ed5..561a741 100644
--- a/src/index.scss
+++ b/src/index.scss
@@ -73,3 +73,8 @@
 .alert-danger {
   @include alert-variant($background-dark-color, $alert-danger-text, $alert-danger-border);
 }
+
+.modal-backdrop.in {
+  filter: alpha(opacity=50);
+  opacity: .5;
+}
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