body {
  background-color: #fff;
}

* {
  box-sizing: border-box;
}

.row {
  display: flex;
  flex-wrap: wrap;
  padding: 0 4px;
}

.column {
  flex: 25%;
  max-width: 25%;
  padding: 0 4px;
}

.column a {
  margin-top: 8px;
  vertical-align: middle;
  width: 100%;
}

a {
  border: solid 1px #fff;
}

img {
  width: 100%;
}

/* Responsive layout - makes a two column-layout instead of four columns */
@media (max-width: 800px) {
  .column {
    flex: 50%;
    max-width: 50%;
  }
}

/* Responsive layout - makes the two columns stack on top of each other instead of next to each other */
@media (max-width: 600px) {
  .column {
    flex: 100%;
    max-width: 100%;
  }
}