Introduces app/panel_style.py, a shared style module every render module now draws through instead of independently duplicating margins/ colors/fonts: Inter Bold/Regular (already vendored, previously only used by widgets/text.py) replace PIL's single-weight bundled default font everywhere else; a per-widget-kind accent color (calendar=blue, tasks=green, weather=black header) replaces plain black-on-white chrome and is centralized in one THEME mapping so a future global theme only needs to touch panel_style.py; a small per-widget gutter separates adjacent widgets without touching grid.py's cell math; header bars, color chips, and the battery icon get rounded corners. Also drops the MUTED gray text color used throughout calendar_render.py and weather_render.py -- a non-palette color that has no close match in the panel's 6-ink palette and dithers into visible speckle once the composited canvas is quantized. Secondary text now reads through size/ weight alone, always exact black. widgets/battery.py and manage_overlay.py's previously-duplicated battery-glyph-drawing code now share one implementation (panel_style. draw_battery_icon). widgets/_shared.py's placeholder image is fixed to use exact palette colors and route through image_pipeline.draw_text, same as everything else -- it was quietly violating both rules already. image_pipeline.draw_widget_border gains an opt-in radius param (default 0, unused by any call site) for a possible future rounded-border setting -- doesn't touch the exact-corner-pixel behavior test_widget_ border.py already pins. Deliberately out of scope: DEFAULT_PALETTE_RGB and the Floyd-Steinberg quantization pipeline are untouched, per the prior reverted measured- palette/OKLab attempt (05b417a/dfe9d701).