.grid-sizer,
.grid-item {
  width: 22.5%;
}

.gutter-sizer {
  width: 3.33%;
}

.grid-item--width2 {
  width: 100%;
}

@media screen and (max-width: 600px) {
  /* 2 columns for small screens */
  .grid-sizer,
  .grid-item {
    width: 49%;
  }

  .gutter-sizer {
  width: 2%;
}
}