Support Light/Dark Themes for the Blog by using toggle switch

**Description**
As a user of our blog, I want to be able to switch between a light and dark theme. This feature will allow users to select their preferred theme based on their personal preferences.

**Acceptance Criteria**

- The blog should have a toggle switch that allows users to switch between light and dark themes
- The selected theme should persist for the same session
- The blog should automatically switch to the user's preferred theme based on their browser settings if available