Fixes #310 Fix: apply invert filter to html instead of body

[tarunashri6]

Fixes #310
Fixes issue with incorrect dark mode rendering caused by applying invert filter on the body element.

Changes made:

• Removed invert filter from body
• Applied invert filter to html element instead
• Removed conflicting background styles

This ensures consistent and correct UI rendering when toggling dark mode.

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[tarunashri6]

Hi, I’ve implemented the fix by moving the invert filter to the html element and removing conflicting body styles. Please let me know if any changes are needed. Thanks!

[pydevsg]

@tarunashri6 please add screenshot of the change