Clean Download

Thunderbird without the boxes.

Six themes that take the outlines, dividers and extra grays out of Thunderbird’s mail window. What is left is your mail, on two calm surfaces.

Download all six themes See each theme View on GitHub

For Thunderbird and Betterbird 153 or later. Free and open source.

Compare the default with
Thunderbird with its default theme: every message sits in its own outlined card and the panes are separated by lines. The same window with the Clean Light theme: flat message rows, no pane dividers.

Up close

The default look separates everything three times over: a border, a gap and a different gray. These themes keep one way of separating things and remove the rest.

Flat message rows

No card outlines, just one thin line between rows. Read mail steps back so unread mail stands out, and the star and row menu wait until you point at a row.

The message list in Thunderbird's default theme.
Default
The message list in the Clean theme.
Clean LightClean Dark

A quieter folder pane

Folder icons share one colour, counts are plain numbers, and the selected folder is a soft pill with no outline.

The folder pane in Thunderbird's default theme.
Default
The folder pane in the Clean theme.
Clean LightClean Dark

One frame, no seams

The window header, the folder pane and the list header lose their dividing lines and their separate grays.

The top of the window in Thunderbird's default theme.
Default
The top of the window in the Clean theme.
Clean LightClean Dark

A matching compose window

Only the toolbar is tinted. The address and subject fields become plain rows, addresses are soft pills, and your message sits in a framed card.

The compose window in Thunderbird's default theme.
Default
The compose window in the Clean theme.
Clean LightClean Dark
Two surfaces
Your mail sits on one colour and everything around it on another. The default spreads about seven grays across the same window.
One accent
Your system’s accent colour, used for selection, folder icons and links, and lightened in dark mode so it stays readable.
Calm reminders
Calendar reminders sit on the page colour as soft rows, with pill-shaped Snooze and Dismiss buttons.

The six themes

Clean Light and Clean Dark tint the sidebar and window frame. The two Mono themes use a single surface everywhere and keep a tint only on the window header. Select a screenshot to see it full size.

Clean Auto and Clean Mono Auto switch between the light and dark versions on their own, following your system’s light or dark setting.

If you use Thunderbird Conversations

The reader on the right of each screenshot is drawn by the Thunderbird Conversations add-on, and a theme cannot reach inside an add-on. A small companion stylesheet does that part: it removes the message outlines and header line, enlarges the subject, quiets the icons, strips the box from the reply field and softens the notification bars.

It is optional. Without the add-on you do not need it, and the reader keeps Thunderbird’s own look.

Download the stylesheet Read its instructions

Install

A theme

  1. Download the theme’s .xpi file. If your browser offers to install it, choose to save it.
  2. In Thunderbird, open the menu and choose Add-ons and Themes.
  3. Click the gear icon and choose Install Add-on From File, then pick the file.
  4. Under Themes, enable it. You can install all six and switch between them there.

From then on the theme updates itself, like any other add-on. To go back, enable one of Thunderbird’s built-in themes in the same list.

The Conversations stylesheet

  1. In Settings, under General, open the Config Editor and set toolkit.legacyUserProfileCustomizations.stylesheets to true.
  2. Open your profile folder from Help, Troubleshooting Information, and create a folder named chrome inside it.
  3. Copy conversations-clean.css into that folder twice, named userContent.css and userChrome.css.
  4. Restart Thunderbird.

These steps are the same on Windows, macOS and Linux. The instructions file has the menus and folder locations for each, plus updating and removal.

Good to know

  • Built on version 153. The themes were made and tested with Thunderbird and Betterbird 153 on Linux. They install on later versions too, but they restyle parts of Thunderbird that can change between releases, so a future update may undo some of the look. Windows and macOS are untested.
  • Made for the card view in three columns. That is the layout in the screenshots. The table view of the message list and the other pane layouts keep more of the default look.
  • Row height is Thunderbird’s. A theme cannot change it. For more room, use the Density setting in the View menu.
  • The screenshots use a demo mailbox. Every person, company and address in them is made up.

Changes

  • 1.1.7Automatic updates. Install this version by hand once; later ones arrive on their own.
  • 1.1.6A fix for the compose window toolbar on macOS.
  • 1.1.5A restyled compose window and calendar reminder window.
  • 1.1.4Softer notification bars in the Conversations stylesheet.
  • 1.1.3Fixes for the window buttons on KDE and see-through dialogs on macOS.
  • 1.1.2Fixes for the selected tab.
  • 1.1.1Your system’s accent colour instead of a fixed blue, and a fix for the status bar.
  • 1.1.0Two new themes, Clean Auto and Clean Mono Auto.
  • 1.0.0First release.

Full details are in the changelog on GitHub.

Download

Version 1.1.7. Take everything in one archive, or only the files you want.

The source code, issue tracker and releases are on GitHub.

Select the image for actual size