git clone https://github.com/yhatt/marp.git
cd marp/sass/themes
cp gaia.sass yourtemplate.sass
cd ../../
npm install

Add the theme to coffee/classes/mds_main_menu.coffee - line 269

            {
              label: '&YOURTEMPLATENAME'
              enabled: @window?
              type: if @window? then 'radio' else 'normal'
              checked: @states.theme == 'yourtemplate'
              click: => @window.mdsWindow.send 'setTheme', 'yourtemplate' unless @window.mdsWindow.freeze
            }


Add the theme to coffee/classes/mds_md_setting.coffee - line 32

      return if basename in ['default', 'gaia', 'yourtemplate'] then "css/themes/#{basename}.css" else null

Start npm

npm start