Making WordPress Gallery (.gallery-item) Responsive?

Shortcode for Gallery:

I’m using a 5 column gallery on an inner page of a website, obviously when the site responds down to mobile and even tablet devices, the images within the gallery keep the default style of width: 20%; and appear far too small.

I have tried adding a media query style to increase the width in percentage, however WP still applies the column class .gallery-columns-5.

Ideally It would be great to have the images in 5 Columns for Desktop’s, 3 Columns for Tablet’s and 1 Column for Mobile Devices.

Would anyone know of a good fix for this?

/ ## Gallery
--------------------------------------------- */

.gallery {
    overflow: hidden;
}

.gallery-item {
    float: left;
    margin: 0 0 30px;
    padding: 0 5px;
    text-align: center;
    width: 100%;
}

.gallery-columns-5 .gallery-item {
    width: 20%;
}

.gallery-columns-2 .gallery-item:nth-child(2n+1),
.gallery-columns-3 .gallery-item:nth-child(3n+1),
.gallery-columns-4 .gallery-item:nth-child(4n+1),
.gallery-columns-5 .gallery-item:nth-child(5n+1),
.gallery-columns-6 .gallery-item:nth-child(6n+1),
.gallery-columns-7 .gallery-item:nth-child(7n+1),
.gallery-columns-8 .gallery-item:nth-child(8n+1),
.gallery-columns-9 .gallery-item:nth-child(9n+1) {
    clear: left;
}

.gallery img {
    border: 1px solid #ddd;
    height: auto;
    padding: 4px;
}

.gallery img:hover {
    border: 1px solid #999;
}

@media only screen and (max-width: 800px)

.gallery-item {
    width: 33%;
}

There is a simple solution for this. Let the gallery use the 5 column grid system and using the @media-queries we can alter it for tablet and mobile. I just tested it on your given URL and it works perfect. But try to remove any custom codes you have used before since I had to remove it in order to use the following code.

/* For displaying 3 columns on tablet */
@media only screen and (max-width: 800px) {
 .gallery-columns-5 .gallery-item {
     width: 33%;
 }
}

/* For displaying single column on mobile */
@media only screen and (max-width: 480px) {
 .gallery-columns-5 .gallery-item {
     width: 100%;
 }
}

.gallery-columns-5 .gallery-item:nth-child(5n+1) {
     clear: none;
}