diff --git a/guacamole/src/main/frontend/src/app/notification/styles/modal.css b/guacamole/src/main/frontend/src/app/notification/styles/modal.css
index ad35bb472..a805ee0e1 100644
--- a/guacamole/src/main/frontend/src/app/notification/styles/modal.css
+++ b/guacamole/src/main/frontend/src/app/notification/styles/modal.css
@@ -18,7 +18,14 @@
  */
 
 guac-modal {
-    display: table;
+    display: -webkit-box;
+    display: -webkit-flex;
+    display: -ms-flexbox;
+    display: flex;
+    -webkit-box-align: center;
+    -webkit-align-items: center;
+    -ms-flex-align: center;
+    align-items: center;
     height: 100%;
     width: 100%;
     position: fixed;
@@ -28,10 +35,12 @@ guac-modal {
 }
 
 guac-modal .modal-contents {
+    -webkit-box-flex: 0;
+    -webkit-flex: 0 0 auto;
+    -ms-flex: 0 0 auto;
+    flex: 0 0 auto;
     width: 100%;
     text-align: center;
-    display: table-cell;
-    vertical-align: middle;
 }
 
 guac-modal {