centre the header on larger screens
centre the header on larger screens

danblundell/verify-local-patterns,BucksCountyCouncil/verify-local-patterns,kenmaddison-scc/verify-local-patterns,kenmaddison-scc/verify-local-patterns,kenmaddison-scc/verify-local-patterns,danblundell/verify-local-patterns,BucksCountyCouncil/verify-local-patterns,BucksCountyCouncil/verify-local-patterns,danblundell/verify-local-patterns