Certificates of completion

Hello, I a many problems when I try to create a custom certificate for my courses 1) I can't remove the certificate label in the upper left corner of my certificate 2) I don't find where to set the PDF orientation as landscape 3) When I change the Text format, save and open the certificate again, it is always set to Certificate WYSIWYG again 4) The Body tokens are not always processed. It may be linked to point 3. 5) When I try to use the Template / Default Certificate, I got an error "Error generating document: Failed to generate PDF: 'background_size' is not a valid CSS2 property."