http://sridharkatakam.com/filterable-portfolio-genesis/

style.css

/*
Filterable Portfolio
---------------------------------------------------------------------------------------------------- */

ul.filter {
    color: #999;
    list-style: none;
    margin-left: 0;
}

ul.filter li {
    float: left;
    margin-left: 1rem;
    margin-left: 10px;
    margin-bottom: 1rem;
    margin-bottom: 10px;
}
ul.filter li:first-child {
  margin-left: 0;
}

ul.filter a {
    background: #333;
    color: #fff;
    display: block;
    padding: 0.5rem 1rem;
    text-decoration: none;
    border-bottom: none;
    font-size: 1.5rem;
    font-weight: 300;
}

ul.filter a:hover, ul.filter a.active {
    background: #0ebfe9;
}

.filterable-portfolio {
    margin-left: -2rem;
    margin-left: -20px;
    overflow: hidden;
}

.portfolio-item {
    float: left;
    margin-bottom: 2rem;
    margin-bottom: 20px;
    margin-left: 2rem;
    margin-left: 20px;
    position: relative;
    width: 270px; /* [main element width - (number of columns - 1)*20]/number of columns */
    /*width: 366px; For 3-columns */
}

.portfolio-item a {
    display: block;
    border-bottom: none;
}

.portfolio-item a img {
    display: block;
    background: none;
    padding: 0;
    border: none;
    -webkit-border-radius: 0;
	-moz-border-radius: 0;
	border-radius: 0;
	width: 100%;
	margin-bottom: 0;
}

.portfolio-overlay {
    bottom: 0;
    left: 0;
    position: absolute;
}

.portfolio-overlay h3 {
    background: #000;
    color: #fff;
    font-size: 1.2rem;
    font-weight: normal;
    margin: 0;
    max-width: 180px;
    padding: 5px 7px;
    text-transform: uppercase;
}

/*-----------------------------------------------------------------------------------*
/* = Isotope CSS Animations
/*-----------------------------------------------------------------------------------*/
.isotope, .isotope .isotope-item { -webkit-transition-duration: 0.6s; -moz-transition-duration: 0.6s; -ms-transition-duration: 0.6s; -o-transition-duration: 0.6s; transition-duration: 0.6s; }
.isotope { -webkit-transition-property: height, width; -moz-transition-property: height, width; -ms-transition-property: height, width; -o-transition-property: height, width; transition-property: height, width; }
.isotope .isotope-item { -webkit-transition-property: -webkit-transform, opacity; -moz-transition-property: -moz-transform, opacity; -ms-transition-property: -ms-transform, opacity; -o-transition-property: top, left, opacity; transition-property: transform, opacity; }
/**** disabling Isotope CSS3 transitions ****/
.isotope.no-transition, .isotope.no-transition .isotope-item, .isotope .isotope-item.no-transition { -webkit-transition-duration: 0s; -moz-transition-duration: 0s; -ms-transition-duration: 0s; -o-transition-duration: 0s; transition-duration: 0s; }

.filterable-portfolio-page .content .entry-header {
	margin-bottom: 1rem;
	margin-bottom: 10px;
}

.filterable-portfolio-page .content .entry-title {
	margin-bottom: 3rem;
	margin-bottom: 30px;
}

@media only screen and (max-width: 1179px) {
	.portfolio-item {
		width: 306px;
	}
}

@media only screen and (max-width: 1023px) {
	.portfolio-item {
		width: 242px;
	}
}

@media only screen and (max-width: 768px) {
	.portfolio-item {
		width: 217px;
	}
}

@media only screen and (max-width: 320px) {
	/* Uncomment the following only if the last filter item is on its own in a separate line like this: http://i.imgur.com/0VD8tmU.png */
	ul.filter li:last-child {
		margin-left: 0;
	}
}