Is working as a marketing website designer for a company that sells detergents to hotels which may include alcohol and indecencies unlawful or lawful?

There is no objection to your work as a marketing website designer for a company that produces detergents and disinfectants, as long as your design does not include prohibited elements such as images of women or music. The company's provision of its products to hotels or places where unlawful acts occur does not make your work unlawful, because your work does not involve any prohibited acts or assisting in them.