Decision around CSS architecture for the shared library. Topic encompasses: CSS preprocessor (Less, Sass, CSS variables), conventions (BEM, utility classes, etc), design tokens, how styles should be exported, etc.
**Considerations**
* **CSS preprocessor:** WVUI, other WMF team-specific libraries, and MediaWiki use Less, while Wikit uses Sass for reasons documented [[ https://docs.google.com/document/d/17ZrSPWX_kvr66gkr0M464URXO4ToRuYhIRefT9ckLpM/edit#heading=h.60e6uxfw7kqc | here ]] (see point 14). Note that CSS variables, a pure CSS option, are not supported in IE11.
* **Design tokens:** See T266688 for details and previous discussion, including [[ https://phabricator.wikimedia.org/T266688#6884221 | WMDE's evaluation of using JSON-based tokens ]]
* **CSS Utility classes:** See T285880 for previous discussion and more links
**Relevant links**
* T258774: Decide on an approach to style scoping (for wikit)
**Decision**
TBD