grimalschi/calque — reverse-engineered prompt

Build me a simple browser based reactive calculator that feels like a scratchpad for math. I want to type lines like 2 inch to cm, cos 45 deg, normal arithmetic, square roots, and unit conversions, and have the answers update right away as I edit.

It should let me create variables, use earlier variables in later lines, define small functions like pow2(x) = x ^ 2, and refer to the previous answer with something like last. I also want indented lists where sections can add up values, like animals with cats and dogs, or plants with nested vegetables.

Make it clean and lightweight, with a small logo area, a big editable calculator area, and readable results. Add handy keyboard behavior too, like duplicating a line with Ctrl+D, changing numbers with Up and Down, bigger changes with Shift+Up and Shift+Down, and indentation with Tab. Use Math.js or look up the current docs if needed.