Colour meaning for any user interface, with no UI toolkit imported:
ui_theme.colour: colour values (24-bit, a terminal's ANSI slots, the terminal default) and terminal palettes.ui_theme.scheme: semantic colours (ThemeColour) and colour schemes.ui_theme.catalog: the built-in schemes and default terminal palettes.ui_theme.wal: pywal'scolors.json, decoded once into a palette and a scheme.ui_theme.depth: a terminal's colour depth (terminal backends only).ui_theme.effects: animated effects as functions of time over semantic colour.ui_theme.splash: TerminalTextEffects effects built in advance (run off the UI thread).ui_theme.clock: one animation clock for every running effect.ui_theme.backend: what a frontend implements (Backend, plusTerminalBackendfor terminals).
A frontend writes one backend adapter. Toad's Textual adapter lives in Toad.