Fixed the dark mode feature when accessing blogs

[Ananya-Nair20]

Description

I have fixed the bug regarding the dark mode in the blogs. After the changes, when you try to use dark mode while accessing blog.html on the browser, the page will turn dark with appropriate style changes to look professional.

Type of PR

• Bug fix
• Feature enhancement
• Documentation update
• Other (specify): _______________

Screenshots

Checklist:

• [x ] I have performed a self-review of my code.
• [ x] I have read and followed the Contribution Guidelines outlined in the project's documentation.
• [ x] I have thoroughly tested the changes before submitting this pull request.
• [ x] I have commented my code, particularly in hard-to-understand areas.