Feat: Dark theme support for Documents

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**Description**:
I'd like to propose adding dark theme support to the llware documentation for a better user experience. Dark mode is increasingly popular for reducing eye strain, especially in low-light conditions. Implementing a dark mode option would allow users to switch between light and dark themes based on their preference or system settings.

**Expected UI Changes**:
- **Background**: Change the background color from white to a dark shade (e.g., `#121212` or `#1e1e1e`) to provide a low-light, high-contrast experience.
- **Text**: Adjust text colors to a lighter shade (e.g., `#e0e0e0` or `#ffffff`) to maintain readability against the dark background.
- **Links**: Use a bright, distinct color for links (e.g., `#1e90ff` or `#ff9800`), ensuring they stand out on a dark background.
- **Buttons**: Style buttons with high contrast, using darker shades for button backgrounds and light-colored text.
- **Code Blocks**: Ensure syntax highlighting adjusts for dark mode, with the background of code blocks becoming darker and the text colors being adjusted for visibility.
- **UI Elements**: Icons, borders, and input fields should be styled to suit the dark theme while maintaining usability and clarity.

**Questions for Maintainers**:
- Do you have any preferences for the approach to implementing dark mode (e.g., Tailwind CSS, custom CSS, or any other framework)?
- Would you prefer an automatic dark mode toggle based on system settings or a manual switch in the UI for users to choose?

**Request**:
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No files, tests, or entry points are named. First identify the documentation site's styling and build entry points, then clarify whether system preference or a manual toggle is required; done means the documented backgrounds, text, links, buttons, code blocks, icons, borders, and inputs remain readable in the dark theme.

Written by the indexing model from the issue text.