fix: improve text visibility in Tailwind Markup Editor

[Mohataseem89]

Summary

This PR fixes the text visibility issue in the Tailwind Markup Editor used in the Live Contributor PR Playground.

Changes Made

• Replaced invalid Tailwind text color utilities:
  • text-slate-250 → text-slate-200
  • text-slate-450 → text-slate-400
• Improved text contrast for better readability in dark mode.
• Preserved the existing UI layout and functionality.

Before

The editor text appeared extremely dark, making the HTML difficult to read.

After

Testing

• Opened Submit UI → Playground
• Verified that the HTML markup is clearly visible.
• Confirmed that the live preview continues to render correctly.
• Verified that Copy Code and Download HTML continue to work as expected.

Fixes #1353

[vercel]

@Mohataseem89 is attempting to deploy a commit to the Trivendra's projects Team on Vercel.

A member of the Team first needs to authorize it.

[Mohataseem89]

Hi @singhtrivendra,

Just following up on this PR. It looks like the Vercel deployment workflow is awaiting maintainer approval before the checks can run.

Whenever you have time, I'd appreciate a review. Please let me know if any changes are needed.

Thank you!