I’ll turn your supplied rules into one standalone responsive calculator page with up to eight inputs and three arithmetic formulas or simple comparisons. It includes input validation, displayed results, reset and CSV export. You receive the source, test results and local run instructions. I’ll check the agreed examples, invalid inputs, keyboard use and narrow and desktop layouts in one specified browser. Data stays in browser memory and is cleared on reload. The local version needs no paid hosting. Existing-app connections, sign-in, databases and deployment can be scoped separately. To scope the work, provide input names, types, units and permitted ranges; the exact formulas or comparisons and output labels; expected input/output examples covering normal values and edge cases; decimal separators and rounding; and the required behaviour for missing values or division by zero where relevant. Supply the page text, style preferences and assets you have permission to use. Name one desktop browser for testing and confirm that browser-memory storage and CSV export fit the task. Use fictional examples rather than personal or production records. I use OpenAI Codex for AI-assisted development. Before processing your brief or source code with that service, I need confirmation that you have the right to share it and permission covering that material. Customer records and source documents remain local unless you separately identify and authorize content for external AI review. Leaving that authorization blank grants no permission to review document or record content with AI. Do not provide credentials or production personal data. The proposed delivery period starts on a date agreed in writing after the required inputs, permissions and platform contracting steps are complete, following the platform’s actual rules. The package includes 1 consolidated written revision within this scope. Defects against the agreed acceptance checks are corrections; new features or changed rules need a separate scope. Briefs, progress updates, revisions and handover are handled in writing.