* chore: prefer calc() over sass math module
* chore: remove unused mixins
* refactor: use css variables for symbolic color names
* refactor: use range syntax for media queries
* refactor: use css variables for symbolic dimensions, units
* refactor: use css variables for symbolic url names
* refactor: use css variables for mime icon urls
* fixup! refactor: use css variables for symbolic dimensions, units
* refactor: replace mime-icon mixin with css variables
* ci: run apt-update before apt-install
Charles Kerr