TITLE: A Cosmic Odyssey — Drifting Through the Nebula at a Whisper

PROMPT: Build a single-file, self-contained HTML page titled "Cosmic Odyssey — Drifting Through the Nebula": a grand, quiet full-viewport cosmic scene. Palette: #05030f space, #6d28d9 nebula violet, #f472b6 pink gas, #38bdf8 atmosphere, #fde68a star. Typography: title system-ui 200 uppercase wide-tracked (letter-spacing .42em), readouts ui-monospace with tabular numerals, log lines Georgia italic. Structure: a fixed full-viewport canvas at z-index 2 for stars and shooting stars; a fixed scene layer at z-index 1 holding five nebula clouds and the planet; and a scrolling <main> with a 100dvh hero and a second 100dvh panel. Nebula clouds are absolutely positioned vmax-sized circles filled with soft radial-gradients (violet at 55% alpha, pink at 44%, a violet floor cloud, a cyan veil near the planet, a small pink wisp) with zero filter — all softness comes from gradient stops — each animated on its own long alternating transform keyframe (54s to 92s) that drifts and breathes the cloud. The planet is a 104vmin circle anchored off the bottom-right corner: a radial-gradient body lit from the upper left, an inset box-shadow pair for the terminator falloff, a repeating-linear-gradient band layer that slowly translates to suggest rotation, a linear-gradient terminator that rotates ±6deg on a 72s loop, and an outer atmosphere ring drawn as a radial-gradient on an element inset -3.5% so the cyan halo hugs the limb. A tiny station silhouette sits on the limb: two 1px truss lines, a small bordered hub, a ring, and a 3px beacon that blinks with a steps(1,end) keyframe. Canvas engine: DPR-scaled, additive ('lighter') compositing, 340 pre-seeded stars with per-star depth, radius, alpha, twinkle speed and one of four colours, drawn with a pointer-driven parallax offset scaled by depth and a scroll-driven zoom about the screen centre; shooting stars are objects with position, velocity, life and trail length, drawn as a linear gradient stroke (white to #fde68a to transparent cyan) plus a bright head dot, spawned randomly every 3.4-7.6 seconds and on every pointerdown at the pointer position. A monospace distance readout counts up continuously from 1,284,902 km with thin-space thousands separators, gated so the DOM is only touched when the integer changes; a velocity line oscillates and is likewise gated. Pointer movement parallaxes the nebula (-30px), the planet (+16px) and the title (+7px) at different rates with easing, and scrolls drive a depth value that scales the nebula 1.5x and the planet 1.24x while fading the title out (opacity is 1 at scroll 0, so a frozen render shows the whole page). The wheel event thickens or thins the nebula by rewriting a --density custom property, clamped between 0.25 and 1.7, and moves a small meter bar. All transforms are cached and only written when the value changes. Everything is frozen under prefers-reduced-motion. All JS in one IIFE in a single inline <script> at the end of body; no external references; the substring "http" absent everywhere.

DESCRIPTION: A quiet, grand cosmic voyage: layered violet and pink gas clouds drift and breathe across a starfield, a huge planet limb curves into the lower right with a cyan atmosphere halo and a slow rotating terminator, and a tiny station blinks against it. A wide-tracked title and a serif log line sit in the dark, while a monospace readout counts the kilometres travelled. The pointer parallaxes the depth layers, scrolling falls deeper into the scene and fades the title, clicking sends a shooting star, and the wheel thickens or thins the nebula.

TECHNIQUES:
- Layered soft radial-gradient nebula clouds with zero filter — all softness from gradient stops, each on its own long alternating transform keyframe
- Planet limb as a huge overflow-hidden circle with radial-gradient body, paired inset shadows for terminator falloff, a translating band layer and a rotating linear-gradient terminator
- Atmosphere glow as a radial-gradient ring on an element inset beyond the planet so the halo hugs the limb
- Additive ('lighter') canvas starfield with per-star depth, alpha, twinkle phase and colour, plus depth-scaled pointer parallax and scroll zoom
- Shooting stars as gradient-stroked trails with a bright head, spawned on a timer and on pointerdown
- Dirty-gated DOM writes: distance and velocity text only update when their rendered value changes; cached transform strings avoid idle style writes
- Wheel-driven density custom property with clamping and a meter bar; scroll-driven depth scaling and scroll-driven title fade (opaque at rest)
- Wide-tracked 200-weight display type, monospace tabular readouts, Georgia italic log lines, steps(1,end) beacon blink, prefers-reduced-motion freeze

INTERACTION: Moving the pointer parallaxes the nebula, planet and title at different rates; scrolling drives the view depth, scaling the nebula and planet toward the camera and fading the title as you fall in; clicking anywhere spawns a shooting star at the pointer (they also cross on their own every few seconds); the mouse wheel thickens or thins the nebula density between 0.25 and 1.7 and moves a small meter; the station beacon blinks on a stepped loop and the distance readout counts upward continuously. With prefers-reduced-motion every cloud, gear, terminator and beacon animation stops, the scene renders as a single still frame, and pointer and click reactions are suppressed.