Righteousness means "as it should be." Evil means "as it ought not to be." When something or someone is righteous, they are as they should be in God's eyes. When a cultural system is righteous, it is operating as it should be in God's eyes.
How does this apply to our lives?
There is a righteousness regarding our identity as children of God. Once we place our trust in the finished work of Christ, God cleanses us and places His Spirit in us, making us righteous before Him. It's a state of existence He gives us.