#portfolio_content { 
    line-height: 0;
  
    -webkit-column-count: 3;
    -webkit-column-gap:   0px;
    -moz-column-count:    3;
    -moz-column-gap:      0px;
    column-count:         3;
    column-gap:           0px;
 }
 
 .img-style{ 
   width: 100% !important;
   height: auto !important;
 }
 

 @media (max-width: 1000px) {
  #portfolio_content {
   -moz-column-count:    2;
   -webkit-column-count: 2;
   column-count:         2;
   }
 }
 @media (max-width: 700px) {
  #portfolio_content {
   -moz-column-count:    1;
   -webkit-column-count: 1;
   column-count:         1;
   }
 }