Responsive E-Commerce Site Build -- 2

I’m building an online store that will launch with well over 100 products, so performance and scalability matter from day one. The entire front-end must be written in clean, maintainable HTML, CSS, and vanilla JavaScript—no heavy frameworks—while still delivering a modern, professional look that adapts seamlessly to mobile, tablet, and desktop screens.

Core shopping experience
Customers need to be able to search or browse via category filters, add items to a fully functional shopping cart, pay online, and log in to track their orders afterwards. Smooth navigation, fast load times, and intuitive UI patterns are critical so visitors can move from product discovery to checkout without friction.

Visual and technical expectations
• A fresh, contemporary design with consistent typography, color palette, and spacing
• Responsive layouts built with flexible grids and media queries
• Semantic HTML5 and modular CSS for easy future edits
• JavaScript written in clear, well-documented modules (ES6 preferred)
• Code organised so another developer can pick it up quickly

I’ll supply product data and any brand assets you need. Please respond with:
1. A brief outline of your development approach
2. An estimated timeline broken into key milestones
3. Your total cost for the full build

Feel free to include relevant samples that show similar e-commerce work. Once we agree on scope and timing, I’ll get assets over right away so you can start coding.