rEFInd is an easy to use boot manager for UEFI based systems. This is a simple theme for it. It comes in a light and dark variant and is based on the rEFInd-minimal theme from Evan Purkhiser and rEFInd-minimal-dark theme from Carlos Pinto.
The function icons are based on those of the rEFInd-regular theme from Alberto Bursi.
Simply download or clone this repository and move it to the directory where rEFInd has been installed (typically /boot/EFI/refind) or a subdirectory therein (e.g. themes/).
Then all you have to do is add a line similar to one of the following to the end of your refind.conf.
Either use:
include themes/refind-simple/dark/theme.conf
if you want the dark theme variant, or
include themes/refind-simple/light/theme.conf
if you want the light theme.