[BUGFIX] Install Tool header fixed on Handhelds

Cleanup CSS and make it usable

Resolves: #71378
Releases: master
Change-Id: Ib93a82d94921d9ef081ce9a6014803967edf58a9
Reviewed-on: https://review.typo3.org/44585


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Stephan Großberndt <stephan@grossberndt.de>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>