Strong CSS architecture starts with defining what CSS should never do

A DEV Community article argues that the foundation of robust CSS architecture lies not in defining capabilities, but in declaring explicit exclusions upfront. The author illustrates how design token systems quietly accumulate misuse — such as storing application state inside CSS custom properties — because nothing in the system is built to refuse such decisions. Without predefined boundaries, stylesheets gradually absorb logic and state that belong elsewhere, making systems harder to maintain over time. The piece contends that exclusions are not gaps in architecture but its most durable component, acting as guarantees rather than limitations. A system that never defines what it will not do, the author warns, will eventually be pressured into doing everything.