.gallery {
    -webkit-column-count: 3;
    -moz-column-count: 3;
    column-count: 3;
    -webkit-column-width: 33%;
    -moz-column-width: 33%;
    column-width: 33%;
}

    .gallery .pics {
        -webkit-transition: all 350ms ease;
        transition: all 350ms ease;
        padding:10px;
    }

    .gallery .animation {
        -webkit-transform: scale(1);
        -ms-transform: scale(1);
        transform: scale(1);
    }

    .gallery .fit-image {
        width: 100%;
        object-fit: cover;
        /*height: 300px; /* only if you want fixed height */
    }

@media (max-width: 650px) {
    .gallery {
        -webkit-column-count: 1;
        -moz-column-count: 1;
        column-count: 1;
        -webkit-column-width: 100%;
        -moz-column-width: 100%;
        column-width: 100%;
    }
}

@media (max-width: 400px) {
    .btn.filter {
        padding-left: 1.1rem;
        padding-right: 1.1rem;
    }
}