Enhance UI components and styles

Commit notes

- Added z-index variables for modal and overlay in app.css to improve layering of UI components. - Updated various Svelte components to use consistent sizing classes for better responsiveness. - Removed unnecessary inline styles and replaced them with Tailwind CSS classes for cleaner code. - Adjusted class names and styles in multiple components to enhance visual consistency and maintainability. - Updated page layouts to use 'min-h-dvh' for better handling of dynamic viewport heights.

These changes aim to streamline the UI and improve the overall user experience across the application.