.containerbg {
    background-image: url('https://www.timetecaccess.com/templates/layout/img/LiftControl/liftcontrol.jpg');
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    position: relative;
    width: 100%;
    padding-bottom: 55%; /* 2:1 */
}

.content {
  display: -webkit-box;
  display: -moz-box;
  display: -ms-flexbox;
  display: -moz-flex;
  display: -webkit-flex;
  display: flex;
  -webkit-flex-direction    : column;
  -ms-flex-direction          : column;
  flex-direction                : column;
  -webkit-justify-content   : center; 
  justify-content               : center; 

  position: absolute;
  top: 0; bottom: 0; left: 20px; right: 20px;
}



/* viewport=768*/
@media screen and (max-width: 48em){

.containerbg {
    background-image: url('https://www.timetecaccess.com/templates/layout/img/LiftControl/liftcontrol_768.jpg');
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    position: relative;
    width: 100%;
    padding-bottom: 30%; /* 2:1 */
}

    .container {
    padding-bottom: 0;
    }
    .content {
    position: relative;
    top: 0; bottom: 0; left: 0; right: 0;
    padding: 40px 20px 40px 20px;
    }

}

/* viewport=480*/
@media screen and (max-width: 30em){

   .containerbg {
    background-image: url('https://www.timetecaccess.com/templates/layout/img/LiftControl/liftcontrol_768.jpg');
	 min-height:520px;

}

}