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I'm looking for a very simple, single page calculation form "website". This single page will have nothing more than a few fields which will be used to calculate gross margin based on the formula found at [login to view URL] The trick is that I would like the user to be able to specify the cost and the desired gross margin and have the price calculated for them automatically The Gross Margin formula is: Gross Margin = (Revenue - Cost) / Revenue. However, given that I want to calculate the revenue for the user, we will need to adjust that accordingly. Revenue = Cost / Gross Margin percentage I am looking for the following in the web page 1. Page should have a white minimalist background. Calculator fields should appear in a raised pop-out. An example of fields that I like can be found under "Fixing Incorrect Email Addresses (Kickstarter Example) on this page: [login to view URL] 2. Logo should be centered on the page at the top. Raised popout should be both vertically and horizontally centered on the page. 3. A logo (to be provided) should appear at the top of the screen (centered). The pop-out box should also be centered. 4. The calculator should have a title (Gross Margin) inside the raised section at the top. The fields (below) should be labelled as follows: "Cost", "Gross Margin", and "Revenue" (the calculated field). 5. Cost and Revenue fields should be formatted as currency ($). Gross Margin should be formatted as a percentage (%) 6. The fields should auto-calculate without a page reload. I assume this will require something like jQuery, but I am open to options. This auto-calculation should also happen when the user changes their input values. 7. The page needs to be mobile-responsive and should adjust to display properly on mobile devices, particularly phones. 8. This page is going to be hosted on Google's App Engine. Please ensure that it can be easily uploaded. URL will be something like <[login to view URL]>/gross margin 9. The underlying code needs plain english comments in-line in the event that I need to change something later. 10. This code needs to work in the latest versions of Chrome, Firefox, Safari, and IE (10, 11, Edge), including the mobile browsers Chrome, Safari and Firefox. 11. This needs to look modern, minimalistic and stylish. Some decent styling examples can be found here: [login to view URL] 12. I don't have any preference for coding language other than it needs to run on App Engine and the forms need to auto-calculate (without page refresh) as the user enters their values.