Is it permissible to design a website for the game "Bingo Online," which may be associated with gambling, given that the designer's role is limited to the external appearance of the site and not its content, and that he will receive payment for this design?

In Sharia, means are subject to the same rulings as their ends. Thus, a means to a bad end takes on its ruling, and similarly, a means to a good end. This is based on the Almighty's saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." Gambling is forbidden in all its forms, and anything that aids in it takes on its ruling of prohibition. Designing websites is permissible as long as it is not known or highly probable that the designer will use them for illicit purposes.