tefkah/zotero-night: a discontinued dark theme for Zotero 6 and the Zotero 7 beta

What Night for Zotero was built to fix

Zotero 6 shipped a light interface and rendered PDFs with their original white pages. For anyone reading papers at night, that meant a bright window and a brighter document pane. Night for Zotero targets both surfaces at once: the UI chrome and the PDF canvas. The README describes it as a "Night theme for Zotero UI & Pdf" that also adds animations and other UI changes, including a cleaned-up tab bar and the removal of borders.

The audience is narrow and specific. It is Zotero 6 users who want a dark application without switching reference managers, and who accept a third-party plugin to get it. The color scheme is based on Nord, with prior work credited to Rosmaninho's Zotero-Dark-Theme, so the palette is not invented from scratch. The repository is written mostly in SCSS, which tells you where the effort went: this is a styling project, not a citation-management tool.

How the plugin darkens the UI and inverts PDFs

The repository layout shows a Zotero extension: chrome.manifest, a content directory, css, defaults, locale, plus an xpi directory. The build pipeline is esbuild driven by esbuild.js, with esbuild-sass-plugin compiling the SCSS, and the package scripts run tsc --noEmit for type checking and zotero-plugin-zipup to produce the packaged extension. The postinstall step runs patch-package, so the build depends on patched node modules rather than stock ones.

For the PDF side, the README is explicit about the mechanism: "currently using CSS filter functions in order to make the pdfs dark, however this is rather slow." That is the central architectural fact. Instead of recoloring PDF content, the plugin applies CSS filters over the rendered pages. It offers two PDF themes, described as a very dark one and one that matches the background color, and a quick toggle for switching between filters. Because the filter is a presentation-layer effect, it does not modify the stored PDF and does not need to parse it. The cost is the performance the README itself flags.

Installing night.xpi and activating the dark theme

Installation is manual. The README says to download the XPI from Releases, and warns that on Firefox you should right-click and choose Save link as. The badge at the top of the README points at the latest release asset, night.xpi. There is no package manager step and no store listing; the artifact is the extension file itself.

# Fetch the release asset referenced by the README badge
curl -L -o night.xpi \
  https://github.com/tefkah/zotero-night/releases/latest/download/night.xpi

In Zotero, install that file as an extension, then activate it. The README gives the exact path: Tools > Night Preferences, and select "Enable Dark Theme". Until you do that, the plugin is installed but inert.

Tools > Night Preferences > Enable Dark Theme

There is no configuration file to edit for normal use. Preferences are exposed through that dialog, which is where the PDF theme choice and the filter toggle live. If you are on the Zotero 7 beta, the README points to a separate zotero-7 branch rather than the main one, so the artifact you want is not the same as the Zotero 6 build.

Discontinued status and the Zotero 7 native dark mode

The most important line in the README is the notice at the top: "Development of this plugin has ceased, as Zotero has introduced it's own native dark mode in Zotero 7." That is a project-ending statement, not a pause. The last push to the repository was on 2026-04-24, but the releases tell a different story about feature work: the newest listed release is 0.1.0-2, tagged as "Night for Zotero 7 ALPHA 0.1.0-2" and dated 2023-09-12, preceded by 0.1.0-1 on 2023-08-20. The package.json version is 0.4.24, which does not match any published release in the list, so treat the version field as build metadata rather than a shipped artifact.

Anyone evaluating this in 2026 should read that as: the Zotero 7 path never left alpha, and the upstream problem it solved was absorbed into Zotero itself. Installing a discontinued theme plugin on a Zotero version that already has a dark mode buys you maintenance risk for a feature you already have.

Known limitations: unstyled popups and slow PDF filters

The README lists two limitations, and both matter more than they first appear. First, "Popup menus do not have proper styling on some platforms." Since the plugin is CSS over Zotero's own DOM, any menu rendered by the platform rather than the application escapes the stylesheet. You get a dark window with light popups, and the README does not say which platforms are affected.

The second is performance. CSS filter functions are applied to the rendered PDF, and the README calls the approach "rather slow." Scrolling a long PDF, or running the filter over a large document, is where that shows up. There is no caching layer described, and no option to pre-render a dark copy of a PDF. If your workflow is page-flipping through scanned documents, this is the wrong tool, and Zotero's own dark mode is the better answer on Zotero 7.

There is also a documentation gap worth naming: the README does not document rollback, nor does it describe what happens to your preferences if you disable the plugin.

Alternatives and how their approach differs

The obvious alternative is Zotero's own dark mode, which the README credits as the reason for the shutdown. The difference is structural: the built-in option is maintained by the Zotero team and ships with the application, while zotero-night is a third-party XPI that patches appearance from outside. If you are on Zotero 7, the built-in mode is the only one of the two with an upgrade path.

On Zotero 6, the closest comparison is the prior work the README credits: Rosmaninho's Zotero-Dark-Theme. zotero-night builds on that lineage and adds the Nord palette, the PDF filter toggle, and the preferences pane. If you want a dark UI but not filtered PDFs, a UI-only stylesheet avoids the slow filter path entirely. That is a real trade-off, not a preference: the PDF darkening is the part with the documented performance cost.

Licence and the cost of keeping it running

The project is GPL-3.0. For an end user installing night.xpi into Zotero, that is unremarkable: you are running the software, not distributing it. The licence matters if you fork the theme, bundle it into a distribution, or ship a modified XPI, because GPL-3.0 carries source and copyleft obligations in those cases. This is a description of the licence, not legal advice; read the LICENSE file in the repository before redistributing anything.

Upgrade cost is the sharper issue. The build depends on a pinned toolchain: esbuild, esbuild-sass-plugin, TypeScript 4.5, ESLint 8, and patch-package applied at postinstall. Rebuilding it years later means resolving those pinned dependencies and the patches directory, which the README does not explain. Since development has ceased, there is no upstream fixing that for you. The practical maintenance plan for a Zotero 6 user is to keep the working XPI file archived locally rather than expecting to rebuild it from source.

Editorial conclusion

Adopt zotero-night only if you are pinned to Zotero 6 and want a dark UI plus inverted PDFs: download night.xpi from the latest release, install it, then open Tools > Night Preferences and select "Enable Dark Theme". Do not adopt it on Zotero 7 or later, because the README states development has ceased now that Zotero ships a native dark mode, and the repository has only an alpha build for the 7 beta on a separate branch. Before installing, verify the XPI matches your Zotero version and read the Limitations section: popup menus are unstyled on some platforms, and PDF darkening uses CSS filter functions that the README calls rather slow.

Frequently asked questions

Official sources

1. Issues
2. License: GPL-3.0
3. README
4. Releases
5. tefkah/zotero-night on GitHub