Look and feel

Loosely, not a checklist: apps should feel like they belong on the same device, not like a foreign screen got pasted into the shell. A few real constraints worth matching rather than reinventing —

• Icons: use the icon: {svg, tileFrom, tileTo} field (see above) rather than baking your own tile markup into render(); it's the same system every built-in app uses now, and you get the fallback letter tile for free if you skip it.
• Chrome you don't own: the LCD frame, nav bezel, and dock are the shell's — render(screenEl) owns the screen area only. Don't reach outside screenEl to restyle the frame around it.
• Everything else — layout, copy, how busy or spare your own screen looks — is yours. This mod doesn't have (and isn't trying to build) a single house style every app has to match beyond "the surface it's actually rendering into is the same LCD every other app on this phone uses."