If you are using the HTML to setup the columns, then you would need the rules below
.page-id-8 .widget.content-3-col:nth-of-type(1) {margin-left:0 !important;}
.page-id-8 .widget.content-3-col:nth-of-type(3) {margin-right:0 !important;}
and change the value to 32% in YOUR existing rule below
.page-id-8 .widget.content-3-col {width: 32%;margin:1% !important; background:#DBE6E0; border: 2px solid#816687;border-radius:10px; padding-top:1%; padding-left:1%;padding-right:1%;position:relative; padding-bottom:60px;}