Why Large CSS Stylesheets Grow Uncontrollably and Become Hard to Maintain

Large CSS stylesheets tend to grow indefinitely because developers feel safe adding new rules but fear removing old ones without proof nothing depends on them. CSS offers no built-in feedback mechanism to flag unused or irrelevant rules, unlike compiled languages that warn about unused variables or imports. This asymmetry means dead code, such as selectors tied to long-rebuilt templates, quietly persists and ships to every user on every page load. The problem is not developer carelessness but a structural gap in the language itself, where silence compounds over time across many contributors. Introducing explicit layer boundaries can make stale rules easier to locate, but does not eliminate the underlying issue of CSS rewarding addition while offering no incentive for subtraction.