fix header for Firefox
fix header for Firefox

RolandStuder/styleguide,manuelroth/styleguide,ComperioAG/styleguide_geologieportal,ComperioAG/styleguide_mont-terri,RolandStuder/styleguide,manuelroth/styleguide,swiss/styleguide,RolandStuder/styleguide,swiss/styleguide,ComperioAG/styleguide_geologieportal,manuelroth/styleguide,ComperioAG/styleguide_mont-terri