@import url('desktop.css') screen and (min-width: 901px);
@import url('middle.css') screen and (min-width: 701px) and (max-width: 900px);
@import url('narrow.css') screen and (max-width: 700px);

input:invalid {
  border:#900 solid 1px!important;
  background-color:#EBBCBC;
}