Build Responsive E-commerce Online Store

I need a complete, ready-to-launch online store for my e-commerce venture. The site must be responsive, cleanly designed, and intuitive for shoppers on both desktop and mobile.

Core scope
• Product catalogue that I can expand or edit easily
• Shopping cart and secure, fully functional checkout
• Basic admin area to track orders and update inventory
• SEO-friendly structure and fast page-load times

I’m open to proven platforms such as Shopify or WooCommerce if that shortens development and keeps future maintenance simple; a lightweight custom build is fine too provided documentation is thorough.

Please include source files, clear setup instructions, and a short walkthrough video or call so I can manage the store on my own once it is live.