The source provides a highly technical and comprehensive overview of CSS stacking contexts and their implementation within Blink, Chrome's rendering engine. It explains the conceptual role of a stacking context as a 3D layer for independent z-axis ordering, detailing the numerous CSS properties and conditions (such as position, z-index, transform, and opacity) that trigger its creation. Furthermore, the text traces the historical evolution of Blink's rendering architecture from legacy WebKit layers to the modern LayoutNG and PaintLayer system, clarifying how internal components like PaintLayerStackingNode and GraphicsLayer manage the complex painting and GPU compositing processes necessary to enforce correct CSS paint order and coordinate mapping. Finally, the overview discusses various edge cases, standards compliance, and debugging tools available to inspect how stacking contexts ultimately influence the final layer composition on screen.