Floating volcanic prison island, ~1...

Floating volcanic prison island, ~140x140, compact start zone. Ground: deepslate, blackstone, polished blackstone, scattered magma blocks, netherrack accents. Ore boulders: gilded blackstone. A large SQUARE mining pit in the island center, recessed ~20 blocks deep, flat floor (this area reserved for the gameplay mine). Prison fortress on one side: deepslate brick cells, iron bars, watchtowers, a big gate facing the central pit. Lava channels along all edges as impassable border. Sparse charred dark crimson-stem trees. Smaller scattered cell blocks, hanging chains, steam vents. Warm hidden lighting (glowstone/shroomlight) so it glows orange and stays mob-free. Island edges crumble into floating rocks. Dark palette, ember-orange glowing accents.