P-table PassThrough [pt] cannot override first row first <td> in p-table (v20.3) & for header span

Describe the bug

I am trying to use PassThrough ([pt]) with PrimeNG v20.3 to override:

1. The <span> inside the <thead> (column headers)
2. The first <td> of the first row in <tbody>
3. The last <td> of the first row in <tbody> I am not sure how to structure the pt object to target these elements specifically.

PrimeNG v20.3 StackBlitz demo code is provided here: https://stackblitz.com/edit/stackblitz-starters-eczg5xvs?file=src%2Fapp%2Fcustom-grid%2Fcustom-grid.scss

How can I correctly structure the pt object (or use any other PrimeNG-provided API) to target thead span, first row first td, and first row last td individually Any examples or guidance would be very helpful.

Pull Request Link

No response

Reason for not contributing a PR

• Lack of time
• Unsure how to implement the fix/feature
• Difficulty understanding the codebase
• Other

Other Reason

No response

Reproducer

https://stackblitz.com/edit/stackblitz-starters-eczg5xvs?file=src%2Fapp%2Fcustom-grid%2Fcustom-grid.scss

Environment

Angular: 20.3.16 Primeng: 20.3.0

Angular version

20.3.16

PrimeNG version

v20

Node version

22.17

Browser(s)

edge, chrome

Steps to reproduce the behavior

1. Go to Stackblitz demo code https://stackblitz.com/edit/stackblitz-starters-eczg5xvs?file=package.json
2. custom-grid component has and from app component I'm passing tablePT tableDT to custom-grid using app.helper.ts
3. Check app.component.scss to see the styles which im trying to override p-table in custom-grid
4. Need to override these styles using passThrough or DesignTokens.
5. Need suggestion on how to use pt for the header span styles and the tbody first row first and first row last to apply styles

Expected behavior

Need suggestion on how to use pt for the header span styles and the tbody first row first and first row last to apply styles how to structure the 'pt' object (or any other PrimeNG approach) to target only these specific elements.
Are there best practices for targeting first/last row or specific cells using pt