Requirement
Users must be able to switch between the supported UI themes at runtime without losing their current page state.
Acceptance Criteria
- Theme switching: with at least 3 supported themes, the selected theme is applied within <= 2 s for >= 95% of theme changes on the top 10 user screens; source: UI automation timing report; horizon: each release affecting theming.
- Preference persistence: the selected theme is restored correctly in 100% of automated regression runs after page reload and new login on the latest major versions of the top 3 supported browsers; source: cross-browser UI test report; horizon: each release affecting theming or session handling.
- Gate behavior: if either threshold is missed, the release is blocked for changes to theming, styling, or user-preference persistence; source: release gate log; horizon: every qualifying release.