dark mode when on pet news, blogs, donate animals and support us page

**Is your feature request related to a problem? Please describe.**
when we are on the pet news page, blogs page, donate animals page and support us page and switch to the dark mode only the header part changes not the background of the page.

**Describe the solution you'd like**
When there is a feature of dark mode, the user wants it to be on the entire screen not only for the header part. I want to add the dark mode to these pages also I talked about.

**Describe alternatives you've considered**
When we switch to these pages, the page heading should be highlighted when we are on that particular page and when we switch to the dark mode the entire screen's background gets changed to the dark mode (i.e. brown colour).

**Additional context**
If I will be assigned this issue I can show you the change I want.