Always follow the established guidelines for:
Are you building or commissioning a website or application? Or are you using a SaaS solution with a customisable front end? Use the UvA design system components.
The full design system is available in Figma. The corporate identity coordinator can give you access.
Sometimes you cannot fully customise a SaaS application. However, you can often apply part of the corporate identity through configuration options or custom CSS. Consult the corporate identity coordinator about the best way to comply with the corporate identity in your situation.
When creating your website or application, also pay attention to: