.two-column-container {
  display: flex;
  gap: 20px;
  margin: 10px 0;
}
.two-column-left, .two-column-right {
  flex: 1;
  padding: 10px;
  background: #f9f9f9;
}
@media (max-width: 600px) {
  .two-column-container {
    flex-direction: column;
  }
  .two-column-left, .two-column-right {
    width: 100%;
  }
}