I need a lightweight yet flexible application that lets me generate square-metre–based quotations for windows and doors made of aluminium and PVC. The workflow should be simple: I enter dimensions, select the profile series, and the system instantly produces an itemised price, pulling its figures from a central price table that I can update myself. Core requirements • Automatic price calculation driven by M² input and adjustable labour, hardware and glazing tables. • Customisable quotation templates so my branding, payment terms and optional notes appear exactly as I want. • An integrated client database that stores contact info, past quotes and status tracking. • The ability to attach or embed simple drawings within the quote—PDF or image—for each item. • Cross-platform delivery: native installers for Windows and macOS plus a browser version that syncs the same data set. The pricing engine must support at least the current aluminium and PVC lines; if you can structure the data so new materials (for example, wood) can be added later without rebuilding the code, that would be perfect. Acceptance criteria 1. Input a sample order (three window types, two doors) and the software produces a branded PDF with correct M² totals and per-item pricing. 2. Update any unit cost in the database, re-run the quote, and see the new figures reflected immediately. 3. Open the same project from Windows, macOS and the web and confirm all data matches. Please outline the tech stack you’ll use, timeline to first test build, and any similar projects you have delivered.