#portfolio {
  display: block;
}

#portfolio li {
  display: block;
  float: left;
  width: 30%;
  max-width: 400px;
  margin-right: 20px;
  margin-bottom: 20px;
}

#portfolio li a {
  display: block;
  padding: 8px;
  background: #fff;
  -webkit-border-radius: 2px;
  -moz-border-radius: 2px;
  border-radius: 2px;
  -webkit-box-shadow: 1px 2px 2px rgba(0,0,0,0.25);
  -moz-box-shadow: 1px 2px 2px rgba(0,0,0,0.25);
  box-shadow: 1px 2px 2px rgba(0,0,0,0.25);
}

#gallery-popup img {
    width: 100%;
}


/** clearfix**/
#gallery-popup  .clearfix:after { content: "."; display: block; clear: both; visibility: hidden; line-height: 0; height: 0; }
#gallery-popup  .clearfix { display: inline-block; }
 
#gallery-popup  .clearfix { display: block; }
#gallery-popup  .clearfix { height: 1%; }

 
/** media queries **/
@media screen and (max-width: 780px) {
  #portfolio li {
    width: 45%;
  }
}

@media screen and (max-width: 550px) {
  #portfolio { 
    text-align: center;
  }
  
  #portfolio li {
    float: none;
    display: inline-block;
    width: 80%;
    margin-bottom: 30px;
  }
}