CSS subgrid lets a grid item inherit and align with its parent grid's column (or row) tracks, so nested elements stay visually aligned even when they're not siblings in the DOM. Currently supported in Firefox 71+ and Safari 16+. A practical example shows a definition list where dt and dd elements inside separate div wrappers align to the same columns as the parent dl grid, using `grid-template-columns: subgrid` on the child divs.
