I'll create a sleek and modern online store design for a gym owner to sell supplements, food plans, training plans, and equipment. We'll use a minimalist aesthetic with a clean layout, white space, bold typography, and a monochrome palette accented with a vibrant color. Let's build this using Next.js and Tailwind CSS.

Let's start by creating the main layout and homepage for the store:

This code creates a sleek and modern online store for a gym owner to sell supplements, food plans, training plans, and equipment. The design features:

1. A clean layout with lots of white space
2. Bold typography for headings and important text
3. A monochrome palette (white, light gray, and dark gray) accented with a vibrant blue color for highlights
4. A minimalist aesthetic focusing on simplicity and ease of navigation
5. A premium feel suitable for fitness and health products

The homepage includes:

1. A hero section with a bold headline and call-to-action
2. A featured products section showcasing top items
3. A category section for easy navigation to different product types
4. A call-to-action section to encourage users to start their fitness journey

The layout is responsive and will adapt to different screen sizes. The header includes a mobile menu for smaller screens, and the grid layouts will adjust from 4 columns on large screens to 2 columns on medium screens and 1 column on small screens.

To further enhance this store, you could:

1. Implement a product detail page
2. Add a shopping cart functionality
3. Create category pages for supplements, food plans, training plans, and equipment
4. Integrate with a payment gateway for checkout
5. Add user authentication for personalized experiences
6. Implement a search functionality

Let me know if you'd like me to expand on any of these areas or if you have any questions about the current implementation!

I'll update the project to use JSX instead of TSX. This means we'll remove TypeScript-specific syntax and use JavaScript with JSX.

Let's update our React project to use JSX:

These changes convert our project from TypeScript (.tsx) to JavaScript with JSX (.jsx). The main differences are:

1. File extensions changed from .tsx to .jsx
2. Removed TypeScript type annotations
3. Added 'use client' directive to client-side components (Header.jsx, Footer.jsx, and page.jsx)
4. Removed the type annotation for the children prop in the RootLayout component

The functionality and structure of the components remain the same. The project still uses Next.js and Tailwind CSS, maintaining the sleek and modern design for the gym owner's online store.

Is there anything else you'd like me to modify or explain about the JSX version of the project?