TITLE The Comet Diner, 3 A.M. PROMPT A CSS-only (no JavaScript) isometric illustration of a small roadside diner at night, built from HTML elements with CSS 3D transforms, gradients, shadows and keyframes, under a big neon billboard that flickers on tube by tube. The viewer can switch the sign and the kitchen on and off, pick a song on the jukebox, and peer in by hovering, all with checkboxes, radios and :hover. Concept: a tiny glowing world in the dark that feels inhabited. Mood: lonely, cosy, cinematic; coffee at 3 a.m. Palette: night indigo-black #0B0F1A ground and sky, neon pink-red #FF3864, neon cyan #2DE2E6, warm window cream #F6F1D1 (interior light, counters, paper cups), deep violet #261447 for building shadow faces and asphalt reflections. Dark page: the concept needs night, and the neon is literal here: actual neon tubes on a sign. Scene (one isometric rig: a container with rotateX(~55deg) rotateZ(45deg) and preserve-3d; every object an extruded box or plane): a diner shaped like a long streamlined railcar: stainless-steel body (built from repeating-linear-gradient horizontal ribbing in cool greys tinted by the neon), rounded end suggested by stepped boxes, a band of large windows glowing cream with silhouettes inside: a counter with five stools, a cook at the grill (a simple figure whose arm moves, flipping), a waitress with a coffee pot who walks the counter and pauses (keyframed), two customers: one stirring coffee (tiny looping arm), one reading a newspaper that occasionally turns a page; pendant lamps; a pie under a glass dome; a jukebox with glowing arches at one end. Outside: a small parking lot with painted bays, one parked car with a long hood and tail lamps, a pickup with its headlights on throwing two cones of light, a telephone box, a newspaper vending box, a fire hydrant, a road with dashed centre line, a streetlamp with a pool of light where moths (tiny dots) circle, puddles on the asphalt that reflect the neon as blurred, wavering pink and cyan smears (flipped, blurred pseudo-elements with animated skew). The sign (signature moment): a billboard on two tall posts standing behind and above the diner: "COMET" in pink neon script/capitals built from CSS-shaped tube segments or text with layered text-shadow glow, "DINER" in cyan block capitals beneath, a shooting-star/comet outline with a tail of three streaks that animate in sequence (chasing lights), and "OPEN 24 HRS" in small cream bulbs. On load the sign is dark; then it strikes: letters flicker on one after another with authentic irregular neon stutter (keyframes with uneven opacity steps per letter, staggered delays), the "M" buzzing and failing twice before catching, the comet tail chasing; as each tube lights, its coloured glow washes onto the roof, the pole, the lot and the puddles (large blurred radial gradients whose opacity is tied to the same animation). One letter keeps an occasional nervous flicker forever. Interaction without JS: a small panel of physical-looking controls at the bottom, each a styled checkbox/radio with label: "SIGN" knife switch (off: sign dark, the scene lit only by windows and streetlamp; on: replays the strike sequence), "GRILL" (off: cook stands still, on: flipping and the grill glows, a patty jumps, and a column of steam curls from the flue stack behind the roof as animated blurred puffs), "RAIN" (overlays slanted rain streaks made from repeating gradients and makes puddle reflections livelier and the asphalt glossier), and three jukebox radio buttons labelled with invented songs ("B4 · Blue Formica", "C2 · Last Bus to Odessa", "A7 · Slow Comet"): selecting one changes the jukebox glow colour and the bounce tempo of musical notes (CSS-drawn quavers) drifting out of the diner door and the pulse of the window light; hovering/focusing the diner swings the whole roof up on a hinge along its back edge (rotateX with a slow ease), showing its lit ceiling and opening the interior to view from above; hovering the pickup makes its indicator blink; hovering the phone box makes it ring (the receiver wiggles and small arcs radiate). Framing typography: beneath the scene, a title in the manner of a paperback noir cover: "The Comet Diner, 3 A.M." in a condensed italic serif (Georgia/"Times New Roman" italic bold, tight) in cream with a pink underline rule, a three-line vignette of prose in small type, a "now playing" line that follows the jukebox, and a one-line hint naming the three hover targets; on wide screens the title sits in the empty lower-left corner beside the scene and the control panel in the lower-right: specific and atmospheric ("Route 9, between a town that closed and a town that hasn't opened yet. The pie is yesterday's. Nobody minds."). Tiny menu board text readable inside when the roof is lifted ("COFFEE .15 · PIE .30 · ADVICE FREE"). The window blinds carry the blurred shadows of the waitress and cook, and the puddle reflections are literally the words COMET and DINER, flipped. A passing car crosses the road every 40 seconds, its headlights sweeping the scene (a moving gradient), and far lightning-free stars twinkle sparsely; a distant freight train of tiny boxes crawls along the horizon line. Responsive: the isometric rig scales with min(vw, vh) units so the scene fits a 360px-wide phone without horizontal overflow (the faded ground corners are clipped); controls stack in a two-column, three-row grid with 44px targets. All inputs focusable with visible cream dashed focus rings. Reduced motion: sign simply on with steady glow, no flicker, no walking figures, no rain animation. DESCRIPTION A tiny diorama of a roadside railcar diner at three in the morning, drawn entirely with HTML boxes and CSS 3D transforms and floating on a disc of asphalt that fades into the dark. Nothing is lit when the page opens except the windows and one streetlamp; then the billboard strikes, tube by tube, the M failing twice, and pink and cyan light spills over the roof, the lot and the puddles, which reflect the words themselves upside down. Inside, a cook flips, a waitress walks the counter and stops to pour, one customer stirs and another turns a page. Around it: a parked sedan, an idling pickup, a phone box, moths at the lamp, a freight train on the horizon and, now and then, a car going somewhere else. A paperback-noir title and three lines of prose frame it, with a small bakelite panel of switches and jukebox keys. VISUAL TECHNIQUES - One isometric rig (rotateX 55deg, rotateZ 45deg, preserve-3d); every object is a single element extruded into a box with its two pseudo-elements as side faces, sized by custom properties - Neon lettering as outlined text with layered text-shadow glow over a dim unlit copy; per-letter stepped keyframes with uneven opacity steps and staggered delays for the strike, plus one letter that flickers forever - Inline SVG comet outline with three tail tubes lit in a chasing sequence; dot-matrix "bulb" lettering made with a radial-gradient clipped to text - Glow washes (blurred radial gradients on the ground, roof and sky) driven by keyframes matched to the letter timings - Puddles whose reflections are generated text, flipped, blurred and wavering with animated skew - Stainless-steel ribbing, checkerboard floor, parking bays, road markings and window mullions all from repeating gradients - Billboarded planes (counter-rotated to face the viewer) for steam puffs, musical quavers, the pie dome, lamp halo and phone rings - Shadow-play silhouettes on the window blinds synchronised with the 3D waitress - Slanted rain built from tiled elliptical gradients moved on the compositor; film grain from an inline SVG turbulence filter - Checkbox, radio, :checked, :hover and :focus-visible selectors for all state; custom properties carry the jukebox colour and tempo INTERACTION MODEL There is no script; every control is a real checkbox or radio with a styled label. The SIGN knife switch cuts the neon, leaving only window and streetlamp light, and throwing it again replays the whole strike sequence. The GRILL knob stops or starts the cook's flipping, the grill glow and the steam. The RAIN rocker fades in slanted rain, glosses the asphalt and makes the puddle reflections brighter and more agitated. Three jukebox keys choose a song, which recolours the jukebox and its floor glow, changes the tempo of the notes drifting out of the door and the pulse of the window light, and updates the "now playing" line. Hovering, tapping or focusing the diner swings its roof open to reveal the counter, the cook, the waitress, the pie and the menu board; the pickup blinks its indicator and the phone box rings. Everything is reachable by keyboard with dashed cream focus rings, and with reduced motion the sign is simply on and the figures hold still.