#469 Improve 404 page UI, responsiveness, and user experience

[Sanika123-art]

Type of Change

Please check the appropriate box that describes your PR:

• 🐛 Bug Fix — Fixes layout and responsiveness issues on the 404 page
• ✨ Content Enhancement — Improves text tone and visual appearance
• 🔥 New Content — Adds new chapters, examples, or significant sections

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Description of Changes

What I changed

• Improved the responsiveness of the 404 page across mobile, tablet, and desktop screens
• Added media queries (including max-width: 600px) for better layout scaling
• Updated text content to be more user-friendly and reassuring
• Refined text colors to reduce visual strain
• Added a backdrop-filter (glassmorphism) effect for a modern, professional look
• Improved button layout and spacing for better accessibility

Why this change

The previous 404 page layout did not scale well on larger screens and the messaging felt slightly abrupt.
These changes improve usability, readability, and overall user experience while maintaining a clean design.

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Additional Notes (Optional)

• This change focuses only on UI and CSS improvements.
• No functional or routing logic was modified.
• Screenshots have been added for visual comparison.
• previous page

After changes

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Checklist

• I have searched open pull requests to avoid duplicates.
• I have built the project locally and verified the changes work as expected.
• I have written clear and meaningful commit messages following the project guidelines.

[netlify]

❌ Deploy Preview for stupendous-kringle-a86e81 failed.

Name	Link
🔨 Latest commit	2e319c2
🔍 Latest deploy log	https://app.netlify.com/projects/stupendous-kringle-a86e81/deploys/698621af450f2800082249fc

[Sanika123-art]

Hi maintainers 👋

The CI / Netlify build failure appears unrelated to the 404 page UI changes in this PR.

The error indicates a missing dependency:
ModuleNotFoundError: No module named 'sphinx_togglebutton'

It seems sphinx_togglebutton is referenced in the Sphinx config but not installed in the build environment.

Please let me know if you’d like me to submit a follow-up commit to add the dependency or if this is already being handled elsewhere.
Thanks!