Some random thoughts, about both the current and a possible future, CSS used in federated wiki.
current
The is currently a fair bit of inline CSS. This is not a good idea. It not only makes it harder to see what is going on, it also makes it harder to make changes.
Inline CSS Audit tries to document the CSS that is currently coded inline in JavaScript. This CSS should be in style sheet files. Where CSS needs to be applied selectivity, a class should be used rather than inline style.
While the cascade is powerful. Those plugins that use stylesheets add a level of unpredictability to the ordering. Which without care can have unpredictable results.
The CSS is old, having grown organically over the last decade. In places it vendor prefixes, even if a non-proprietary approach has become available.
The core CSS contains a number of plugin specific rules. These would better be part of the plugin.
future
Cascade layers might provide a useful supplement to the order based cascade. *Though it might just add an extra level of complexity.*
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