Yaru MATE is the default GTK theme for Ubuntu MATE 21.04 and newer. This snap can be installed to appropriately theme snapped applications. There is a Yaru MATE icon theme snap to compliment this snap:
Snaps are applications packaged with all their dependencies to run on all popular Linux distributions from a single build. They update automatically and roll back gracefully.
Snaps are discoverable and installable from the Snap Store, an app store with an audience of millions.
Snap is available for Linux Mint 18.2 (Sonya), Linux Mint 18.3 (Sylvia), Linux Mint 19 (Tara), Linux Mint 19.1 (Tessa) and the latest release, Linux Mint 20 (Ulyana).
You can find out which version of Linux Mint you’re running by opening System info from the Preferences menu.
On Linux Mint 20, /etc/apt/preferences.d/nosnap.pref needs to be removed before Snap can be installed. This can be accomplished from the command line: