[Site]: Missing theme toggle switch on website pages

[ayush00git]

Current State

The toggle switch which allows toggle between the dark and light mode is only visible for the Blog and Case Studies page, https://apisix.apache.org/blog/tags/case-studies/
The website do offers light and dark mode for all its pages, but when viewing the site in the desktop, the toggle switch is missing for all the other pages, except for Blog and Case Studies page.
Example for Docs pages -

and in Case Studies page -

Steps to reproduce the bug -
Open the website in laptop - https://apisix.apache.org/
You'll not find the toggle switch there.
It's only visible for the pages - https://apisix.apache.org/blog/ and https://apisix.apache.org/blog/tags/case-studies/

Desired State

Expected behavior-
The website offers light and dark theme for all its pages, in the mobile view the toggle switch case is there, for desktop view, it should be there too.

Would you like to fix this issue?

Yes! Count me in

[ayush00git]

Hey, I am making the changes, as i'm done, i'll raise a PR.