This is my adaptation of Matcha theme by jakubzet for Mailspring E-mail Client.
The original Matcha theme is work of Vince - check his awesome piece of work in Matcha GTK repository. Kudos for the author for a wonderful theme and inspiration!
For more details about this great theme please visit the Repository of the autor Matcha theme repository
Download ZIP-Archive and extract. Run Mailspring, select Edit - Install Theme... and choose folder.
Made with Love by Heriberto Delgado.