Please paste the code below to Page Settings > Other Scripts > Add New > Custom CSS of your Live Editor page.
div.pp_default .pp_content_container .pp_right, div.pp_default .pp_bottom .pp_left, div.pp_default .pp_bottom .pp_middle, div.pp_default .pp_bottom .pp_right, div.pp_default .pp_content_container .pp_left, div.pp_default .pp_top .pp_right, div.pp_default .pp_top .pp_middle, div.pp_default .pp_top .pp_left {background: transparent !important;}
Ensure to click Save and Continue or Save and Close when done.