Is it permissible to work on building a website for a company specialized in building banks?

There is no objection to designing a website for a company that builds interest-based banks, unless the company's work is exclusively limited to building these banks, or predominantly so, or if the website includes a specific advertisement for those banks and an invitation to deal with them. In these cases, designing the website is forbidden due to its包含 co-operation in sin and aggression.