Design and develop a responsive e-commerce website for a new online store. The website should include features for product browsing, adding items to a cart, secure checkout, payment gateway integration and order tracking.

Key Features:

• Product catalog management
• Shopping cart and checkout functionality
• Secure payment gateway integration
• Order tracking system
• Responsive design (adapts to different devices)

Other details will provided to the selected candidate

Freelancer should have to sign the NDA before sharing more details