Chrome extensions can darken web pages, but Manifest V3 sandboxing prevents them from touching the actual browser frame (tabs, toolbar, omnibox). Chrome Appearance Switcher bridges this gap by pairing a modern MV3 extension with a lightweight local native messaging companion on Windows. With a single click or global hotkey (Alt + Shift + D), Chrome repaints its actual UI between Light and Dark mode in real time without restarting the browser.