I need a streamlined internal web application where every functional team can log only the cost breakdowns they own. The moment a cost line is saved, the system must compile all inputs into a single master cost sheet that the sales team can view in real time. From that sheet the sales group should be able to apply their margin, generate an editable offer form, tweak any commercial text as needed, and e-mail the offer directly to the buyer while automatically copying the responsible sales person. Until the buyer clicks “accept”, the same offer record has to stay open for revisions; each resend should overwrite the previous version so we keep one clear audit trail. Once the buyer accepts, the sales user will hit an “Accepted” button and the software must trigger a contract in our existing .NET-based ERP (API or database call—whatever is cleaner). Key points that must be built in: • Two role levels: team member (cost entry only) and sales (margin, offer, contract). • Clean, spreadsheet-like cost-entry UI for quick typing and attachment of notes. • Automatic consolidation of all cost entries into one protected sheet. • Offer generation in our branded PDF/HTML template sent via SMTP or Microsoft 365 mail. • Status tracking: Draft → Sent → Revised → Accepted → Contracted. • Integration hook to push the accepted data set into our ERP so the contract prints with zero re-keying. If you have experience with role-based web apps, live Excel-style grids, and .NET integrations, your approach, tech stack preference, and an outline of milestones will help me evaluate fit.