A self-contained, 30-second interactive web experience.
Built for a Codex meetup, then revisited as the models around it changed. In July 2026, the project returned to the workbench with GPT-5.6 Sol—two days after its general release and one day before Claude Fable 5's included subscription access was scheduled to change. The result is both a small interactive artwork and a record of what it means to keep caring for an AI-made project after the event is over.
| State | Desktop | Mobile |
|---|---|---|
| Initial |  |
 |
| Playing |  |
 |
| Result |  |
 |
The four-milestone, same-viewport comparison is preserved in the July 13 visual history audit.
| Date | Episode |
|---|---|
| June 2026 | “What would a day off for Codex look like?” became a 30-second constellation garden for a Codex community meetup. |
| June 20–25 | The visual language was rebuilt around an original Afterglow identity, documented in DESIGN.md, reviewed through a project-local OmD pilot, and deployed through GitHub and Cloudflare Pages. |
| July 11 | The repository was reopened with GPT-5.6 Sol. The live experience was tested again, missed accessibility states were fixed, reduced-motion support was added, and the moment was recorded instead of being allowed to disappear into commit history. |
| July 13 | A Galaxy S24 report turned the revisit into a rendering-safety and mobile-UX pass: pixel and frame budgets were bounded, desktop-site mode gained a safety path, Night Sky / Paper Sky became explicit play scenes, sharing moved into the first result viewport, and the first build was visually audited against the current experience. |
Read the full entry: 2026-07-11 — revisiting Afterglow.
The follow-through is recorded in the Galaxy S24 incident report and mobile rendering decision.
Open index.html directly, or serve the folder:
python3 -m http.server 8000Then visit http://localhost:8000.
- Move the mouse or use arrow/WASD keys.
- On mobile, press and drag anywhere on the play surface to steer directly.
- Collect the drifting lights.
- At 30 seconds, the garden becomes a personalized final scene.
- Play in
🌙 Night Skyor☀️ Paper Sky; the current scene is always visible, persists locally, and is preserved in the exported image. - Export the played scene as a 1200 × 630 PNG or hand it to LinkedIn, X, Telegram, KakaoTalk, and the native share sheet. Mobile keeps every destination available and places sharing before replay. External handoffs explain when the PNG must be attached separately.
No login, API key, build step, network request, or external service is required.
The animation uses an optimized Canvas 2D renderer with cached glow sprites, a bounded pixel budget, a static star layer, debounced resize allocation, and background-tab pausing. Touch hardware targets 45fps in the normal mobile layout and uses a 30fps safety path when desktop-site mode expands the viewport. WebGPU remains an evaluated experimental direction rather than the default renderer; see ADR-0002.
Append ?debug=1 to the URL to display the active renderer, measured FPS, and device-pixel ratio.
Use the direct result preview to inspect sharing without waiting for the 30-second play session:
- Result and all six share destinations: https://dayoff.tmcowork.com/?preview=result
- Result plus renderer/FPS diagnostics: https://dayoff.tmcowork.com/?preview=result&debug=1
On Galaxy S24, open each link in Chrome Beta and Samsung Internet in the normal mobile layout. Confirm that 🌙 Night Sky opens on a dark surface, ☀️ Paper Sky switches immediately to warm white, the primary device share action appears in the first result viewport, and all six destinations remain reachable by vertical scrolling. The preview uses a fixed sample sky and does not change the normal entry flow. Full measurements and the distinction between automated approximation and physical-device testing are recorded in the S24 scenes and sharing verification.
| State | Screenshot | What it proves |
|---|---|---|
| Night Sky · before |  |
The selected Night label previously remained on a warm-white intro, making the state ambiguous. |
| Night Sky · after |  |
Night selection now changes the intro background, text, borders, and prompt contrast immediately. |
| Paper Sky · after |  |
Paper selection remains visibly distinct and readable on the warm-white surface. |
| Paper Sky · result |  |
The primary share action and the six-destination panel are exposed without playing for 30 seconds. |
The visual system is documented in DESIGN.md. It uses an original OpenAI-inspired product language while preserving the Afterglow concept and avoiding official logo or layout reproduction.
- Source: GitHub (
johnjheejin/codex-day-off) - Hosting: Cloudflare Pages
- Custom domain:
dayoff.tmcowork.com