/* General */
.container {
  margin: 10px;
  width: 98%;
  white-space: nowrap;
}

.item {
  width: 25%;
}

.flex {
  display: flex;
  flex-wrap: nowrap; 
  overflow: auto;
}
.flex-item {
  flex: 0 0 auto;
}

@media screen and (min-width: 0px) and (max-width: 600px) { /* small screens */
  .container {
    margin: 2px;
  }
  
  .item {
    width: 100%;
  }
}