Install this version:
emerge -a =media-gfx/mate-themes-calculate-18-r6
If this version is masked, you can unmask it using the autounmask tool or standard emerge options:
autounmask =media-gfx/mate-themes-calculate-18-r6
Or alternatively:
emerge --autounmask-write -a =media-gfx/mate-themes-calculate-18-r6
# Copyright 1999-2025 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
# $Header: $
EAPI=7
DESCRIPTION="Mate theme for Calculate Linux"
HOMEPAGE="https://www.calculate-linux.org/packages/media-gfx/mate-themes-calculate"
SRC_URI="https://mirror.calculate-linux.org/themes/mate/${PF}.tar.bz2"
LICENSE="Apache-2.0"
SLOT="0"
KEYWORDS="amd64 x86"
src_install() {
insinto /
doins -r .
}