.main-row {
  margin: auto;
  width:750px;
  height:1000px;
  border: 1px solid red;
  margin-top: 15%;
  display: grid;
  grid-gap: 20px
}

.rec {
}

.rec-1 {
  border: 1px solid green;
}

.rec-2 {
 border: 1px solid purple;
}

.rec-3 {
 border: 1px solid blue;
}