Hoi,
sorry I don't understand something...
As I understood You asked about "Custom Css For A Specific Page"
but where is the problem?
Custom CSS in SPPB can be used in two ways:
- Each Page have field for Custom CSS for whole page
- Custom CSS can be added for selected addons inside addon settings
You don't need Sourcerer from regular labs to add few lines of custom CSS! Just read SPPB documenation first "How to use custom CSS" and "How to use shortcodes": https://www.joomshaper.com/documentation/sp-page-builder/sp-page-builder-3/how-to-tips#documentation-heading-20
Don't make simple things difficult for yourself. Use tools that you already have. Nothing more, nothing less.