CSS max width, max height, CSS responsive https://www.agernic.com/css-tutorial/css-max-width-max-height-css-responsive.html

max-width-height-responsive.css

.div-box1  {
  width: 100%;
  max-width: 450px;
  height: 210px;
  border: 1px solid #73AD21;
  background-color: red;
  }
.div-box2 {
  width: 100%;
  height: auto;
  max-height: 250px;
  border: 1px solid #73AD21;
  background-color: red;
  }
.div-box3
 {
  width: 100%;
  height: auto;
}