You're hosting a kids' sleepover and need to figure out how many sleeping bags fit in the living room floor space without anyone being squished. Build a single-page app where the user enters the room's length and width (in feet), and the size of each sleeping bag (standard kid or adult preset, or custom dimensions). The app instantly calculates how many sleeping bags fit in a neat grid layout, displays a simple top-down visual grid showing the arrangement, and shows leftover floor space in square feet. The user can toggle between landscape and portrait sleeping bag orientation to see which fits more. No auth, no backend — just a clean, instant calculator with a friendly visual grid output.