Build a single-file WebGPU "material study" page called "Castle Jelly", in the style of my jelly diorama series (Pirate Jelly / Island Jelly): a square block of wobbly jelly lake on a table in a paper studio, cut faces showing candy strata, italic serif masthead "Castle / Jelly.", glass control panel on the right, "How to play" line at the bottom-left, UI in English, mobile bottom-sheet layout.
The diorama: a fairy-tale castle on a cliff. The back-left of the block is a plateau whose front is a sheer wall of candy-striped rock (layer-cake strata that match the block's cut faces, a talus under the lake), meshed from an SDF with surface nets, mossy where it faces up. On the lawn: a cream castle with round towers, glossy pink/lilac/blue cone roofs, gold finials, fluttering pennants, crenellated walls, a great hall, arched windows (dark glass by day, lamplight at night), a gatehouse with a drawbridge, a brazier by the gate, gummy pines, flowering bushes, reeds. A river wells up from a spring, runs past the gate under the drawbridge and pours off the lip as a waterfall that arcs down into the jelly lake — and keeps going inside the jelly: a fraying plume, bubbles driven down then rising, bright threads of current streaming along the lake floor. The falls pound the surface (shallow-water waves, foam, spray, mist). A little royal galleon (blue hull, white sails, crown standard) sails laps of the lake.
Interactions: Fireworks (rockets off the towers, coloured bursts that light the castle and the lake; automatic at night), Lower/Raise bridge, Royal salute (ship fires, splash), Wishing coins (into the pool under the falls); tap a tower / the gate / the brazier / the ship, drag the water to make waves, tip the block, throw coins and balls, bend the pines. Sliders: Firmness, Waterfall (flow), Wave damping, Time of day (noon → sunset → night with stars). Flavours: Glacier, Rose, Lilac. Shadows, caustics, refraction through the jelly, fixed-step physics.
中文译文
构建一个单文件 WebGPU“材质研究”页面，名为“Castle Jelly”，风格与我果冻立体模型系列（Pirate Jelly / Island Jelly）一致：纸艺工作室里的一张桌子上，一块方形、颤动的果冻湖，切面露出糖果分层，斜体衬线报头“Castle / Jelly.”，右侧玻璃控制面板，左下角一行“How to play”，界面为英文，移动端底部抽屉式布局。
立体模型：悬崖上的一座童话城堡。方块的后左侧是一处高原，其正面是糖果条纹岩石构成的陡壁（与方块切面一致的千层蛋糕式地层，湖面下方有碎石坡），由 SDF 通过 surface nets 网格化生成，朝上的面覆盖着苔藓。草坪上：一座奶油色城堡，有圆形塔楼、光亮的粉色/淡紫色/蓝色锥形屋顶、金色顶饰、飘动的三角旗、带城垛的城墙、一座大厅、拱形窗户（白天是深色玻璃，夜晚透出灯光）、带吊桥的门楼、门边的火盆、软糖松树、开花的灌木和芦苇。一条河从泉眼中涌出，流过城门、从吊桥下穿过，并从边缘倾泻而下形成瀑布，弧形落入果冻湖——而且继续在果冻内部延伸：一缕逐渐散开的羽状水流、被压下去又升起的泡泡、沿湖底流动的明亮水流细丝。瀑布拍打水面（浅水波、泡沫、水花、雾气）。一艘小小的皇家大帆船（蓝色船体、白色船帆、王冠旗）在湖上绕圈航行。
交互：Fireworks（火箭从塔楼升起，彩色爆裂照亮城堡和湖面；夜间自动触发）、Lower/Raise bridge、Royal salute（船上开炮，溅起水花）、Wishing coins（投入瀑布下方的水池）；点按塔楼／城门／火盆／船，拖动水面制造波浪，倾斜方块，投掷硬币和球，弯折松树。滑块：Firmness、Waterfall (flow)、Wave damping、Time of day（正午 → 日落 → 星空夜晚）。口味：Glacier、Rose、Lilac。阴影、焦散、穿过果冻的折射、固定步长物理。
