Admin Dashboard Sidebar

Construct an admin dashboard layout using CSS Grid, featuring a sidebar for navigation, a main content area with statistics cards, and a clean responsive structure.

The dashboard should include a persistent sidebar on the left with navigation links, and a main region showing key metrics and data. On smaller screens, the layout should adapt so content remains usable.

Use CSS Grid to define the overall page structure: a fixed-width sidebar plus a flexible main area. Ensure the sidebar has a distinct background and the cards use a grid of their own.

Make the layout responsive so that on narrow viewports the sidebar stacks above the content or collapses, keeping the page readable.

Test that the grid maintains alignment across different screen sizes and that all cards render correctly.