The dark palette lives as a single :root[data-theme='dark'] block in
tokens.css; theme.ts and the pre-paint public/theme-init.js (external file
because the prod CSP forbids inline scripts) always resolve the stored
ui.theme.mode to a concrete data-theme, so 'system' needs no @media
duplicate and follows live OS changes via matchMedia. color-scheme flips
per theme (native controls/scrollbars), paired theme-color metas track the
effective theme, and the new Appearance settings section offers the
three-way choice as native radios (device-local, like #170). Label chips
gain a chip-outline ring so arbitrary user colors stay separated on the
dark canvas; useEffectiveTheme() is exported for the later pond-scoped
theming stage (ADR 0018).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QRtCnB3uLdQtFmvp9HXcRX
