How to use

• Weeks run Monday to Sunday. Switch between Week, Month and Year above the navigation — Month and Year both let you jump straight to a period with the picker next to the arrows.
• Log sale: enter your salesperson code to identify who's logging it, whether it was a contract or cash, the customer, the motorcycle (comes out of inventory automatically), the sale amount and its cost. Commission is calculated instantly.
• Projected gross margin = sale amount − motorcycle cost − commission − 9.75% sales tax on the sale amount. It's called "projected" because a contract customer can still default partway through their payments — the full sale amount isn't guaranteed cash in hand. It's called "gross margin," not "profit," because it doesn't include your other business costs — rent, payroll, GPS trackers, supplies, etc.
• Edit a sale to correct any field after logging it — useful when a customer paid a down payment, made a few installments, then backed out. Changing the motorcycle model adjusts inventory for both the old and new model.
• Delete a sale asks for the owner code — only you can remove a logged sale. It returns the motorcycle to inventory.
• Add and Remove inventory both require the inventory code. Add sums when new stock arrives; Remove subtracts (damaged bike, count correction, etc.).
• New product and Discontinue product (same inventory code) manage the catalog itself -- add a model your dealership starts carrying, or retire one you no longer stock. Discontinuing only affects what's available going forward; past sales logged under that model keep showing it.
• New product asks for the model's cost and sale value, and Edit product lets you rename a model and/or set or update its cost and sale value later (useful for models already in the catalog). Renaming updates the model everywhere, including past sales logged under the old name. Each stock card then shows an estimated gross margin = sale value − cost − 9.75% sales tax on the sale value. This is a catalog-level estimate, separate from a sale's own "Projected gross margin," which uses that specific sale's actual amount and cost.
• When logging a sale, the motorcycle cost field auto-fills from that model's catalog cost (if set) -- you can still edit it if this particular unit cost something different.
• The Total stock value tiles above Inventory add up every unit currently in stock: at cost (what it's worth if you had to replace it) and at sale price (what it's worth if you sold all of it today). Models with quantity in stock but no pricing set are left out of both totals -- run Edit product on them if a total looks low.
• Add salesperson, Remove salesperson and Rename salesperson (owner code) manage who can log sales and at what contract commission. Renaming updates every past sale too, so commission totals by person stay correct; removing keeps their sale history intact, it just stops them from logging new ones.
• Every change is saved to data.json on your server right away — works from any computer or phone that opens this page.
• Salesperson, inventory and owner codes are for identification, not real security — don't treat them as secret passwords, and keep the owner code to yourself.
• The access code on first visit works the same way — it stops casual visitors, not someone determined (anyone who opens their browser's dev tools can read it directly in the page's source). It's remembered per device after the first correct entry, so staff won't see it again on the same computer or phone.