$ sudo apt-get update
$ sudo apt-get install libcss-minifier-xs-perl 

libcss-minifier-xs-perl is installed in your system.

Make ensure the libcss-minifier-xs-perl package were installed using the commands given below,

$ sudo dpkg-query -l | grep libcss-minifier-xs-perl *

You will get with libcss-minifier-xs-perl package name, version, architecture and description in a table

libcss-minifier-xs-perl package basic information: