TI-30XS Calculator Emulator Based on Javascript in Joomla

I need a calculator that emulates the look and functionality of the Texas Instruments TI-30XS calculator. It is for a website that I run. It needs to function on mobile as well as desktop environments and for mobile it should be somehow adaptive to both a portrait orientation and a landscape one. I have attached an image. I'm a bit concerned about the size of the calculator on mobile devices. It may be necessary to behave differently in landscape vs portrait in order to fit the screen. It should also be responsive in that it doesn't need to be refreshed when moving from landscape to portrait. I would like it to be based on Javascript and styled with CSS I think. Further it is for a website based on Joomla. I would like to have a slide out drawer that can be retracted to show/hide the calculator. Currently we have a calculator (wrong calculator version) that I worked up that I attached screenshots of to show the desired behavior. The current drawer doesn't quite resize correctlt without refreshing the screen.