.parent {
  display: flex;
  width: 800px;
  max-height: 300px;
  gap: 20px;
  overflow-x: auto;
  background-color: blue;
  padding: 20px;
}

.box {
  background-color: aqua;
  height: 200px;
  width: 200px;
  flex-shrink: 0;
}