PROMPT USED
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Build a standalone, fully offline HTML5 page: an orrery of the solar system with
orbiting planets and hover info tooltips. Palette: deep space, glowing sun.
Signature: concentric orbit animations with transform-origin, hover tooltips,
starfield background. Hard constraints: one self-contained .html, all CSS in one
<style>, all JS in one <script>, zero external dependencies (system fonts only,
no CDN, no external images/SVG files), responsive 320px→4K, valid HTML5, must run
by double-click with no network requests. WOW bar: Awwwards/SiteInspire-caliber,
distinctive art direction, real motion, one signature effect. A matching .txt
with the same base name must accompany it.


TITLE
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Systema Solis — a brass-and-nebula orrery where every world keeps its own time.


DESIGN DESCRIPTION
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Against a deep-space gradient veiled in violet, cobalt and rose nebulae, a full
starfield twinkles and drifts with gentle parallax behind a circular, ringed
"stage". At its heart burns a pulsing sun — a layered radial-gradient sphere with
a screen-blended, slowly rotating conic corona and an breathing outer glow. Eight
worlds orbit on concentric rings: Mercury, Venus, Earth (with its own moon), Mars,
band-banded Jupiter, ringed Saturn, faintly-ringed Uranus and deep-blue Neptune —
each a shaded, volumetric marble sized and coloured for clarity rather than to
scale, with alternating prograde/retrograde motion and Keplerian-ish period ratios
so the inner planets race while the outer giants turn imperceptibly. Hovering any
planet freezes the mechanism and raises a glass "ledger" tooltip beside it,
positioned in screen space so it stays upright no matter the orbit angle, listing
diameter, distance from the Sun, day length, moon count and temperature. A slim
glass control bar lets you pause the whole system, scale time from a crawl to a
whirl, and toggle the orbit lines and the world labels.


MAJOR VISUAL TECHNIQUES
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- A devicePixelRatio-aware <canvas> starfield with per-star twinkle phases, warm/
  cool star tints, and mouse-driven parallax drift for depth.
- JS-driven orbital motion: each planet's angle = start + dir·(elapsed/period)·2π,
  positioned with trig over the stage center, so radii scale live with the stage
  via a fraction of its half-extent — fully responsive, no clipping.
- Volumetric planet shading using a highlight radial gradient plus a CSS ::after
  terminator (light→dark) overlay; gas-giant banding via repeating-linear-gradient.
- Saturn/Uranus rings as screen-blended conic-gradient ellipses tilted on the
  planet; Earth carries a fast-orbiting grey moon computed from its parent's position.
- A layered glowing sun: radial-gradient body, rotating conic corona (::before),
  breathing halo (::after) and dual box-shadow bloom.
- A single shared glass tooltip positioned from getBoundingClientRect so it stays
  screen-upright; hovering a planet freezes the orrery so the card is readable.
- Glassmorphic control bar (play/pause, speed slider, orbit + label toggles) with
  fluid clamp() sizing and a compact layout under 520px.
- prefers-reduced-motion: static starfield, frozen orbits, still sun.


INTENDED INTERACTION MODEL
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- Ambient motion: all eight planets (and Earth's moon) orbit continuously at
  period-weighted speeds, the sun pulses and its corona rotates, and stars twinkle
  + drift, so the system is alive the moment the page opens.
- Hover/tap a planet → the entire orrery freezes, a ledger tooltip appears next to
  the world (viewport-clamped), and it tracks the planet's position; moving off the
  planet resumes the mechanism.
- Move the mouse to shift the starfield in parallax, giving the cosmos subtle depth.
- Controls: Play/Pause halts orbits and the sun; the Speed slider (0.1×–4×) scales
  time live; the Orbits and Labels checkboxes toggle the guide rings and world names.
- Responsive: the stage is a square sized to min(90vw, 86vh, 840px) and every orbit
  radius is a fraction of it, so the orrery holds its proportions from 320px to 4K;
  controls and tooltip reflow on small screens.
- Reduced-motion users get a still, inspection-ready orrery with no auto-rotation
  or star drift.