Membership invoice print

Hi together,
i have tested the membership function. I tested it on Sandbox/Testing and its works well. Then the User can print the invoice, but when i print this invoice it’s all messed up and the sweetdate theme will also be printed with then invoice. How can i fix it? Have you a idea? My idea was that when a user click on print, then opens a popup with the clean invoice without sweetdate theme, then the user can print the clear invoice…

Thanks