body {
  width: auto;
  min-width: 320px;
  min-height: 100vh;
}

main {
  width: min(100%, 460px);
  margin: 0 auto;
  padding: 24px 18px;
}

@media (max-width: 460px) {
  .grid.two { grid-template-columns: 1fr; }
}