html, body {
  margin: 0;
  padding: 0;
}

* { box-sizing: border-box; }

.container {
  display: grid;
  grid-template-columns: 1fr;
  width: 100%;
  max-width: 100%;
  gap: 1rem;
}

.element {
  width: 100%;
  padding: 1.25rem;
  min-width: 0;
}

@media (min-width: 70em) {
  .container { grid-template-columns: 1fr 1fr; }
}