diff --git a/public/style.css b/public/style.css
index 700cb02..aa07ddb 100644
--- a/public/style.css
+++ b/public/style.css
@@ -954,6 +954,12 @@ input.form-control[type=file] {
   margin-left: 3px;
 }
 
+/* Modal backdrop */
+
+.modal-backdrop {
+    opacity: 0.75;
+}
+
 /* Modal confirm window */
 
 .modal-dialog {