1. Any decent setup using the CSS Language Server Protocol would warn you about conflicting variables. 2. Custom properties can be scoped to a particular part

1. Any decent setup using the CSS Language Server Protocol would warn you about conflicting variables. 2. Custom properties can be scoped to a particular part of the DOM [1]. 3. @function has shipped Chrome; custom properties defined inside of an `at` function are local custom properties. So are the parameters. 4. Local properties stay local unless the outside explicitly references them (which it can't without knowing they exist) [1] Limit the reach of your selectors with the CSS @scope at-rule -- https://developer.chrome.com/docs/css-ui/at-scope https://developer.chrome.com/docs/css-ui/at-scope