Dark mode PDFs in Chrome
Dark mode extensions restyle web pages and stop at the edge of a PDF. Convert the file and it opens dark in Chrome, and everywhere else too.
No account required. Preview free, then £0.99 per document.
Why extensions cannot reach a PDF
A dark mode extension works by rewriting a page's styling — it needs a web page to rewrite. Chrome does not display a PDF as a web page; it hands the file to a built-in viewer that draws it directly. There is no styling for the extension to alter, which is why an extension that darkens the entire internet stops dead at a PDF. The extension is not failing so much as arriving somewhere it cannot work.
The force-dark flag does not cover it either
Chrome's experimental force-dark setting rewrites page colours for sites that have no dark theme of their own. It operates on the same web content extensions do, so a PDF is outside its reach for the same reason. Turning it on changes a great deal of the browser and nothing about the document you are reading.
Screen filters darken the wrong thing
Whole-screen tinting and inversion tools do reach the PDF, because they sit in front of everything. That is also the problem: they dim your entire display, invert photographs along with text, and switch off the moment you stop reading. Nothing about the file has changed, so it is white again on your phone and white again when you print it.
Changing the file instead
Converting produces a normal PDF that is dark in Chrome's viewer, in Firefox, in Acrobat, on a phone, and offline. No extension, no flag, no filter. Text stays selectable and Ctrl+F still finds words, because the conversion edits colour instructions rather than flattening pages into pictures.
Questions
Why does my dark mode extension not work on PDFs in Chrome?
Because extensions restyle web pages, and Chrome renders PDFs in a built-in viewer rather than as a web page. There is no styling to rewrite, so the extension has nothing to act on.
Does Chrome have a built-in dark mode for PDFs?
No. Chrome can follow a dark system theme for its own interface, but the PDF itself keeps the colours stored inside the file.
Is a screen filter a reasonable substitute?
It darkens the page, but it dims your whole display, inverts photographs, and stops the moment you turn it off. The file is unchanged, so it is bright again anywhere else you open it.
Will the converted file still be searchable in the browser?
Yes. Text stays selectable and searchable, so browser find still works, and links inside the document keep working too.