I have already built a clean, fully responsive web store in pure HTML and CSS that highlights an organized product layout, intuitive navigation, and consistent styling. The shop will cater to “Web Developer” products, and the visual side is complete; what I now need is the business logic that turns it into a working online shop. Core features to implement • Shopping cart that updates totals in real time and persists between pages • Product-level user reviews with rating display and simple moderation tools • Site-wide search that returns relevant items quickly, without external libraries • Secure checkout supporting Credit/Debit cards and PayPal (stand-alone or through a common gateway such as Stripe/PayPal SDK) Technical notes – The existing codebase is lightweight, so please keep all additions framework-free on the front end; vanilla JavaScript is preferred. – Back-end language is flexible—PHP, Node, or Python are all acceptable as long as the setup stays simple to deploy. – Any database you choose is fine (MySQL, SQLite, or a flat-file approach) so long as installation steps are clear. – All new code must be clearly commented so I can follow along and maintain it later. Deliverables 1. Updated source files with the new functionality fully integrated 2. SQL or migration scripts (if applicable) 3. A brief README that explains folder structure, environment setup, and how to extend each feature 4. Short video or screenshots demonstrating the full purchase flow from search to checkout I will provide the current repository as soon as we start so you can branch off cleanly.