@media only screen and (max-width: 900px) {
  .page-header h1{
    font-size: 36px !important;
  }
}

@media only screen and (max-width: 600px) {
  .page-header h1{
    font-size: 24px !important;
  }
  .wp-call-button span{
  font-size:20px !important;
 }
}