# Theme System Cross-Browser Compatibility Report **Agent:** qa-automation-engineer **Date:** 2026-03-21 **Task:** Cross-browser and cross-device testing of the dark/light theme system **Test file:** `tests/theme-cross-browser.spec.ts` **Reference spec:** `tests/theme.spec.ts` (persistence/ARIA coverage) --- ## Executive Summary The dark/light theme system has been audited for cross-browser compatibility across **Chrome, Firefox, Safari/WebKit, and Edge** (desktop and mobile). The implementation uses proven, widely-supported primitives: CSS custom properties (`html.dark` toggle), `localStorage`, `matchMedia`, and a blocking inline `