CSS Subgrid Helper

.parent {
  display: grid;
  grid-template-columns: 1fr 2fr 1fr;
  gap: 1rem;
}

.child-spanning {
  /* Span all columns to enable subgrid */
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: subgrid;
}

.grandchild {
  /* Now aligns to parent grid tracks */
}

/* Use case: card grid with aligned headers */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  align-items: start;
}
.card {
  grid-row: span 3;
  display: grid;
  grid-template-rows: subgrid;
  row-gap: 0;
}

/* Browser support: Chrome 117+, Safari 16+, Firefox 71+ */