New concepts
display: grid, grid-template-columns, grid-template-rows, grid-column, grid-row, grid-template-areas, grid-area, repeat(), minmax(), auto-fit, auto-fill, justify-items, align-items, justify-content, and align-content.
Grid after Flexbox and positioning
Flexbox arranges content primarily along one axis. Grid defines rows and columns together. Unlike positioned layout, Grid keeps items participating in a shared layout system rather than removing them from normal flow.
Lessons
Checkpoint
Create a responsive page with named header, sidebar, content, and footer areas. Use repeat(), minmax(), and auto-fit for one repeated section, then explain whether each alignment decision moves items inside cells or the full track collection.