modal widths are fixed

src/scss/styles.scss

@@ -202,6 +202,18 @@ input, select, textarea {
     }
 }
 
+.modal-dialog {
+    width: $modal-md;
+}
+
+.modal-sm {
+    width: $modal-sm;
+}
+
+.modal-lg { 
+    width: $modal-lg;
+}
+
 .modal-body {
     h3 {
         font-weight: normal;