.gallery-item {
float: none !important;
margin: 0 !important;
padding: 10px !important;
box-sizing: border-box;
width: auto !important;
}
.gallery-caption {
padding-top: 10px; 
}
@media (min-width:500px) {
.gallery-item {
float: left !important;
width: 50% !important;
}
}
@media (min-width:800px) {
.gallery-item {
float: left !important;
width: 33% !important;
}  
}