Create a 1024x1024 square app icon — premium, vibrant and dimensional, in the style of top App Store featured apps.

Subject: <single hero for <AppName> — a friendly soft 3D character/mascot with simple dot eyes, OR a bold symbolic object/abstract form; instantly readable at small sizes>

The look (north star): one dimensional hero rendered in soft glossy 3D (or rich 2.5D) — smooth color gradients, soft studio lighting, gentle rim light, a subtle soft glow, rounded volumes and real depth — centered on a FULL-BLEED vivid branded background (solid color or smooth gradient) that reaches all four edges. Saturated, high-contrast, polished, delightful. Like a soft glossy jelly/clay form with tasteful highlights.

Background: fill the ENTIRE square edge-to-edge with a bold branded color or smooth gradient (e.g. a vivid blue gradient, or a deep dark backdrop for high contrast). Never plain white, never empty. The background is part of the icon.

Subject treatment: dimensional and glossy — soft rounded 3D forms, smooth gradients, gentle highlights and rim light, a subtle inner glow, clear depth and volume. Rich saturated color. One strong, simple silhouette.

Composition: the hero centered, filling ~60-80% of the canvas with comfortable breathing room; the branded background fills the rest to the edges. One focal point, no clutter.

If the brand is monochrome (one ink + one accent), STILL make it fully dimensional and premium — glossy 3D form, tonal gradients within the brand color, soft lighting, a bold full-bleed background. Never a flat single-color glyph.

Do NOT: flat monochrome pictogram, black-on-white glyph, single-color line/silhouette icon, plain SVG/vector symbol, sticker or clip-art; plain white or empty background; a smaller rounded card/icon floating inside the canvas (no icon-in-icon, no outer margins); baked rounded app-icon corners or device-rounded corners (keep a full square with sharp 90 degree corners — iOS applies its own mask); any text, letters, numbers, monograms or watermark; realistic human faces or photos as the main subject; real or trademarked brand logos; mirror chrome, garish neon, or lens flares.

Color palette: <brand colors as names — e.g. "vivid blue gradient background, soft white-to-sky-blue glossy character with subtle highlights">. High saturation, strong contrast on the home screen.

Technical: square 1:1; background bleeds to all four edges with sharp corners; keep critical details within the central ~70% so an Android circular/rounded mask never clips them; punchy and readable at 60px (blur test).

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Remember: **icon and adaptive-icon changes require a native rebuild** (`npx expo run:ios` / `npx expo run:android`, or a new EAS build) — they will NOT appear on hot reload. The favicon is a web asset and reloads normally.
</post_processing>

<render_verification>
File inspection is not enough — confirm the icon on a device/simulator after a native rebuild.

1. Rebuild the dev client (`npx expo run:ios` or `npx expo run:android`).
2. On the home screen confirm: the new art shows (not the old/default), iOS applies a clean rounded mask with **no double-rounding and no white/transparent corner halo**, and the mark is readable at home-screen size.
3. Fail the run if the icon still shows the previous art, a flat glyph, or a corner halo. Fix before reporting completion.
</render_verification>

<failure_modes>
- **Flat monochrome glyph / black-on-white pictogram** (the most common, worst failure) → the prompt leaned minimal/matte; re-emphasize "premium vibrant dimensional, glossy 3D, full-bleed branded background, NOT a flat SVG symbol", and regenerate.
- White/transparent corner halo after the iOS mask → baked rounded corners; run the step-1 scale-up + center-crop, verify `hasAlpha no`, rebuild.
- Generated icon has transparency → App Store rejection; flatten onto the brand bg (`magick ... -alpha remove -alpha off`).
- Android adaptive icon looks cropped at the edges → subject sat outside the central 66% safe circle; increase padding or regenerate with explicit padding.
- Icon unchanged after editing the PNG → no native rebuild; hot reload never updates the launcher icon.
- Prompt rejected by safety filter → reword neutrally, simplify to one plain paragraph.
- Mark turns to mush at small size → too detailed; simplify to a single strong silhouette (blur/64px test).
</failure_modes>