Violevo/Fortnite-Drop-Calculator ? reverse-engineered prompt

Build me a simple Fortnite drop calculator web app that helps figure out the best place to jump and when to deploy the glider so you can land as fast as possible.

I want an interactive map where I can drag three markers for the bus start, bus end, and target spot, then see the optimal jump point and glider start point update right away as I move them. It should use a clean, lightweight setup with plain JavaScript, HTML, and CSS, and the map should be shown with Leaflet. Please make it work locally by opening the page in a browser, and also let it use the Fortnite API map data, with a fallback image if that fails.

Keep the calculations simple and focused on fastest time to land, and make the updates smooth so dragging doesn’t feel laggy. If you need to check current docs for the map or API, look them up online first.