TailAdmin/free-nextjs-admin-dashboard ? reverse-engineered prompt

Build me a clean, modern admin dashboard starter for a web app using this project as the base. I want it to feel production ready and easy to customize, with a responsive layout, a polished sidebar, dark mode, and a good looking main dashboard with charts, tables, summary cards, and basic data visuals using mock data.

Please include the common screens people expect in an admin panel, like sign in and sign up pages, profile settings, form elements, alerts, dropdowns, modals, and a custom 404 page. If the template already has things like calendar or chat style screens, keep those in and make them feel consistent with the rest of the UI.

The goal is to have a complete back office style dashboard I can open and immediately understand, not just a pile of components. Make sure navigation works, the pages feel connected, and the design is accessible and mobile friendly. If you need to, look up the latest docs for anything current.