our system and space CSS definitions are growing and make them hard to maintain manually.
We do have a system-wide CSS. While a space has no CSS itself, it will use the system-wide CSS. Fine.
Though, many space administrators in our Confluence system wanted small CSS additions for their space which did not make sense to include into the system-wide CSS.
The current implementation of the CSS requires (at least up to 5.4) to copy the whole system-wide CSS to the space, and then add the additional space-specific customizations.

Suggestions:
1. I would prefer if the space-specific CSS would simply overwrite (merge with) the system-wide CSS, so we don't need to repeat them in each space. The pages should first read the system CSS, then the space CSS, then apply the combined content to the pages. This would eliminate a lot of redundant content in the space CSS'.
2. When upgrading from one Confluence release to another, frequently the spelling of CSS has changed. In case they are used in (potentially many) space CSS, all of these CSS need to be updated. In installations with many spaces, this can become a huge amount of work. So I'm looking for an administration tool which allows to add/delete/replace blocks of CSS to all space CSS where certain conditions are met (e..g. the existence of a certain CSS key which has been obsoleted or modified)