TYPO3 Core

With version 11.0 the frontend (based on Twitter Bootstrap, but possibly also with others) breaks - at least as soon as the admin panel is installed and activated and you are logged into the backend.

The reason for this is the inclusion of _legacy.scss (https://github.com/TYPO3/TYPO3.CMS/blob/master/Build/Sources/Sass/_legacy.scss) in adminpanel.scss (https://github.com/TYPO3/TYPO3.CMS/blob/master/Build/Sources/Sass/adminpanel.scss#L13) which makes changes to various TWB classes.

For the backend this is of course ok, but in the frontend the CMS should not change any styling that does not explicitly belong to the CMS component, the "admin panel" in this case.

The adminpanel.css is the only TYPO3 stylesheet of which I currently know that it has this behavior - should it also occur with other files, the behavior must of course be adjusted there as well.