.layout--twocols {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.layout--twocols > .layout__region {
  flex: 0 1 100%;
}

@media screen and (min-width: 40em) {
  .layout--twocols > .layout__region--column {
    flex: 0 1 calc(50% - 8px);
  }
}