anishad829/grid-ceiling-calc-emergent ? reverse-engineered prompt

Build me a simple web app for calculating a ceiling grid layout and material estimate from room measurements.

I want to enter the room size, ceiling height, and a few basic spacing values, then get back a clear breakdown of what I need, like the grid layout, number of pieces, and a rough total. It should be easy to use, look clean, and make the results simple enough for someone who is not technical to understand. If it helps, include a basic frontend with form inputs and results, and whatever backend logic is needed to do the calculations. Please make it feel polished, with validation for bad inputs and a nice summary view at the end. If you need to check current docs or best practices online while building it, go ahead.