/* Base (mobile first) */
.responsive-card {
 width: 20px;
  height: 20px;
}

/* Tablet (min-width: 640px) */
@media (min-width: 640px) {
  .responsive-card {
    width: 200px;
    height: 200px;
  }
}

/* Desktop (min-width: 1024px) */
@media (min-width: 1024px) {
  .responsive-card {
    width: 300px;
    height: 300px;
  }
}



#scroller > * {
  display: block; /* or flex if they were flex children */
  overflow: hidden;
}