/* Mobile up to 599px. Loaded only at that width. */
  .nav ul { display: none; }
  .sec-head, .paper .grid { grid-template-columns: 1fr; }
  .row { grid-template-columns: 56px minmax(0,1fr); }
  .row p { grid-column: 2; }
  .builds { grid-template-columns: 1fr; }
  .build:nth-child(n) { grid-column: auto; min-height: 0; }
  .steps { grid-template-columns: 1fr 1fr; row-gap: 48px; }

/* small-phone refinements */
  .item { grid-template-columns: 1fr; }
  .item .n { display: none; }
  .actions { justify-content: flex-start; }
  .steps { grid-template-columns: 1fr; }
  .nav .btn { padding: 10px 14px; }