Frame.theme (7 presets in app/theme_tokens.py) drives font family, corner radius, drop shadow, and an accent hue for every modern-style widget's header/accent region. Rich accent colors (not just the 6 flat panel inks) are approximated via denser Bayer stippling confined to just that region (html_render.ordered_dither_regions), so icon/text content elsewhere stays exactly as crisp as it is today -- verified directly against real Chromium renders, both in unit tests and via run-server. "classic" is a byte-identical no-visual-change default: weather's header keeps its original fixed blue gradient, tasks/calendar keep their flat THEME_* ink. Themes are purely stylistic -- battery's charge-level color, calendar/ tasks' per-owner event chips, and text's own per-widget font choice are never touched.