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Change Thunderbird to a dark theme

The most popular linux distibution for developers who are developing .net core applications is ubuntu. Primarily due to it's ease of use and also it comes pre-packied with a number of tools, one of which is the default Thunderbird email client.

As far as email clients go, Thunderbird has all the functionality you need out the box and is easily enhanced by adding and installing add-ons available via the add-ons Manager.

The only issue I have with Thunderbird is that the default UI is somewhat dated and often looks clunky when compared with the other tools I use on a daily basis. Fortunately this is quite easy to change. Particularly after a Github user spymastermatt has crafted custom Thunderbird .css for the e-mail client’s window chrome.

In the pack are a number of different themes which really add more than a little style to the email client. However, my personal favourite is the full dark theme.

Custom Thunderbird themes

Although installing a theme is not exactly difficult, it still isn't a complete 1 click easy. But as developers we are no doubt familiar with this.

The reality is that custom thunderbird themes are not themes in the true sense, rather they are customisations of the userChrome.css to change the look of Thunderbird as it starts up.

All of the theme files make use of the EncodeSans Narrow font and use a custom set of .svg icons to replace the default Thunderbird icons.

Install Thunderbird themes

Download the theme .zip from GitHub

Once downloaded extract the .zip archive and rename the folder to chrome.

rename folder

Open the chrome folder and then open userChrome.css using Gedit or favourite text editor.

Navigate to line 13 or thereabouts and replace @import "themes/system.css"; with @import "themes/fulldark.css";


Save you changes

We can now move the entire folder to ~/.thunderbird/[random letters and numbers].default/.

To do this navigate to you Home folder then use Ctrl + H to see your hidden files.

thunderbird folder

We are now done and all that remains now is to open Thunderbird and appreciate the theme. Included in the theme pack are several different themes and if you would like to explore the different selections you only need to change the .css name . i.e. ‘dark.css’, ‘fulldark.css’, ‘light.css’, etc.

dark thunderbird
Gary Woodfine
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