Chrome still ships no dark mode for its built-in PDF viewer. Open a white paper at 1am and you get a flashbang. So you go to the Web Store, install the extension with the most installs, click it, and… nothing happens. The page stays white. I went and read the manifests of the top results to find out why. Two reasons, and both are boring. Reason 1: the popular ones only handle file:// The extension named "PDF Dark Mode" (about 10,000 users, rated 2.5) declares exactly this: ...