* {
  box-sizing: border-box;
}
.columnTwo .childContainer {
  background-color: rgb(65, 161, 94);
  width: 150px;
  height: 150px;
  margin: 10px;
}

@media all and (max-width: 900px) {
  .columnThree {
    display: none;
  }
}

.card {
  display: grid;
  grid-template-columns: 300px 1fr 300px;
  height: 1000px;
  overflow-y: auto;
  text-align: center;
}

.columnOne .childContainer {
  height: 100px;
  background-color: lightpink;
  margin: 10px;
}

.columnThree .childContainer {
  height: 100px;
  width: 100%;
  background-color: lightpink;
  margin: 10px;
}

.columnTwo {
  display: flex;
  flex-flow: wrap;
  margin: 2px;
  overflow-y: auto;
}

.columnOne {
  overflow-y: auto;
}
.columnThree {
  overflow-y: auto;
}