Revert "Fix csslint again"

This reverts commit 58ac80c4e083175787bdfe0dcfaabacf44bdd733.
Revert "Revert csslint change"

This reverts commit 833cc4ebda5c6e8afc1f8a6b88f98ab99593bfbd.
Revert "csslint does not recognise flexbox - fixed"

This reverts commit c7744f5dffdad3138d143d903579d83842c72041.