Implementing GPT-2 Entirely In CSS

Why it matters

A developer has built a working implementation of GPT-2 that runs entirely in CSS, without JavaScript or WebAssembly, using variable font files to perform matrix multiplication. The project began as a response to an online prompt about absurd 'programming' languages, and it treats CSS as a substrate for neural-network inference rather than styling. Two core obstacles shaped the work. First, CSS lacks array primitives, so every weight had to be written directly into the stylesheet. Second, CSS variables do not store values in memory; the browser instead copies and recursively unrolls expressions, which broke computation until each variable was registered with the @property at-rule, forcing the browser to resolve and keep actual numbers. The experiment reveals how much computation modern CSS can express through calc() and related functions, while also showing its practical limits, since the stylesheet-based approach became enormous in size and crashed browsers when scaled toward the full model.