* {box-sizing: border-box;}

.img-zoom-container {
  position: relative;
}

.img-zoom-lens {
  position: absolute;
  border: 1px solid #d4d4d4;
  /* 36 ~= 20 * 64 / 36; (ratio of img to result width) */
  width: 36%;
  height: 20%;
}

.img-zoom-result {
  border: 1px solid #d4d4d4;
  position: absolute;
  top:0;
  left:0;
  width:100%;
  height:100%;
}