In Cassius, I am making it possible to mechanically reason about the layout of a web page. It's been a lot of work! The hardest part has been writing a logical specification for most of the CSS rendering algorithm; in other words, the hardest part is the part where I write a web browser. But there are some core ideas in Cassius separate from the CSS specification, and to make those clear in this post I'll write a toy version of Cassius from scratch. Toy CSS To make toy Cassius somewhat shorte...
