.masonry { /* Masonry container */
    -webkit-column-count: 4;
    -moz-column-count: 4;
    column-count: 4;
    -webkit-column-gap: 1em;
    -moz-column-gap: 1em;
    column-gap: 1em;
   
    -moz-column-gap: 1.5em;
    -webkit-column-gap: 1.5em;
    column-gap: 1.5em;

}

.item {
    display: inline-block;   
  
    width: 100%;
    -webkit-transition: 1s ease all;
    box-sizing: border-box;
    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
 
}

    .item img {
        max-width: 100%;
    }

@media only screen and (max-width: 320px) {
    .masonry {
        -moz-column-count: 1;
        -webkit-column-count: 1;
        column-count: 1;
    }
}

@media only screen and (min-width: 321px) and (max-width: 768px) {
    .masonry {
        -moz-column-count: 1;
        -webkit-column-count: 1;
        column-count: 1;
    }
}

@media only screen and (min-width: 769px) and (max-width: 1200px) {
    .masonry {
        -moz-column-count: 2;
        -webkit-column-count: 2;
        column-count: 2;
    }
}

@media only screen and (min-width: 1201px) {
    .masonry {
        -moz-column-count: 3;
        -webkit-column-count: 3;
        column-count: 3;
    }
}