Make llight theme seamless just like dark theme.

[satisfiedsingle]

Hi I recently looked into the 'Apps' app and noticed that the app has a new design layout. The app's title bar (where the text "Apps" is mentioned) seamlessly switches colors based on the theme mode selected along with all other elements.

But when we come look at the 'PDF Viewer' app, things seem to be different. The 'PDF Viewer' app's title bar (where the text "PDF Viewer" is mentioned) seems to be stuck on the same black layout despite the change in theme.

My humble suggestion is to make the 'PDF Viewer' app to work similar to the 'Apps' app in response to the change in theme.