fix style of input

routes/settings/instances/add.html

@@ -28,12 +28,12 @@
 <style>
   @media (max-width: 767px) {
     input {
-      width: 90%;
+      max-width: 90%;
     }
   }
 
   input {
-    width: 250px;
+    max-width: 250px;
   }
 
   form.add-new-instance {