Css Output Efficiency

Keep generated site CSS small by reusing shared role rules and avoiding duplicate declarations across part, page, and content-type stylesheets. Place each common rule at the broadest site or theme style scope that needs it, and add only necessary overrides. When changing shared styles, inspect the production CSS output and representative pages to confirm that the rule is emitted once per theme, related UI remains consistent, and CSS size does not grow through duplication. Measure page performance when CSS changes are material; do not assume reuse alone guarantees a Lighthouse score.