Light mode toggle does not work when clicking theme switch button

[ChiragTankan]

Bug description

When clicking the theme toggle button in the top-right corner, the site does not switch to light mode. Dark mode remains active and no visible change occurs.

Steps to reproduce

1. Open the site
2. Click the theme (light/dark) toggle in the top-right corner
3. Observe that light mode is not applied

Expected behavior

The site should switch between dark and light themes when clicking the toggle button.

Actual behavior

Light mode does not activate after clicking the toggle.

Environment

• Browser: Chrome / Firefox (mention yours)
• OS: (mention yours)
• Project: Docsy sample site

Additional context

This appears to be related to theme switching logic or missing CSS variables for light mode.
I would like to work on fixing this issue.

[ChiragTankan]

Hi maintainers 👋
I’d like to work on this issue. Could you please assign it to me?