Extracted theme toggle functionality into a new `app-theme` component to improve modularity and reusability. Integrated theme settings with a service using cookies for persistence and introduced the `THEME_MODE` enum. Updated header component to utilize the new theme switcher and removed inline implementation.
Moved header content logic based on `current_page` input for reusability. Updated styling and layout structure to improve maintainability and accommodate dynamic titles and subtitles.
Teriuihi