This source provides an extensive overview of CSS Grid Layout, a powerful two-dimensional system for web design. It details Grid's specifications and capabilities, explaining how tracks are sized, items are placed using lines or areas, and the functionality of subgrid for nested layouts. The document contrasts Grid with Flexbox, highlighting their distinct strengths in terms of dimensionality and layout flow, while also exploring forward-looking features like masonry layoutand container queries. Finally, it offers a deep technical examination of how Grid is implemented in Chrome's Blink engine (LayoutNG), covering the layout algorithm, intrinsic sizing, fragmentation, and performance optimizations.