Modal overlay not properly centered on screen"

[ChayanDass]

Describe the bug

Modal overlay was not properly centered on the screen. The modal positioning was using fixed positioning with transform translate, which caused alignment issues.

To Reproduce

Steps to reproduce the behavior:

1. Go to 'Settings' page
2. Click on 'Add Service' button (in Pinning Services section)
3. See modal overlay not properly centered
4. Or click on 'Generate Key' button (in IPNS section)
5. Or go to 'Files' page and click on 'CLI Tutor Mode' button
6. See error in modal positioning

Expected behavior

Modal should be properly centered on the screen with the overlay covering the entire viewport and the modal content centered both horizontally and vertically.

Screenshots

Affected Modals:

• Add Service modal (Settings → Pinning Services)
• Generate Key modal (Settings → IPNS)
• CLI Tutor Mode modal (Files page)

Desktop (please complete the following information):

• OS: Linux
• Browser: Chrome/Firefox
• Version: Latest