CSS 3D Transforms: How Someone Built DOOM in a Browser Without WebGL [2026]

CSS 3D Transforms: How Someone Built DOOM in a Browser Without WebGL [2026] Somewhere around 2013, a web developer named Keith Clark published a demo that broke frontend engineers' brains. A fully navigable 3D world — corridors, walls, lighting, shadows — rendered entirely with CSS 3D transforms and HTML div elements. No <canvas> . No WebGL. No game engine. Just the browser's own rendering pipeline doing something nobody designed it to do. I remember opening that demo and immediately popping open DevTools, convinced there had to be a hidden canvas somewhere. There wasn't. Every wall, floor, and ceiling was a transformed div . And it ran smoothly. That moment changed how I thought about what CSS could do. More specifically, it changed what I thought "rendering engine" actually meant. The techniques behind this are more clever than most developers give them credit for. Here's how all of it works. How Does CSS Create a 3D World From Flat Elements? CSS 3D transforms rely on one core mathem