Having trouble with custom print formats

Is there anyone who has worked with custom print formats in ERP Next using html and css because I’m finding it difficult to work with it. The problem is when do preview, the design is totally different from default preview, full page preview and pdf preview.
On fullpage preview, it’s showing the exact design I made, but on pdf preview, the design is totally changed. Is there anyone who faced this before, and how I can I go about it

Maybe share some screenshots? If confidential you can PM me I can provide help.

Alright thanks