#portfolio .portfolio-items {
margin: -15px; /*Vertical space before and after the portfolio items*/
}
#portfolio .portfolio-item {
float: left;
padding: 15px; /*Margin between portfolio items*/
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
-o-box-sizing: border-box;
-ms-box-sizing: border-box;
box-sizing: border-box;
cursor: pointer;
margin: 0 1% 1% 0; /*Don't know but changing to 0% didn't fixed*/
overflow: hidden;
position: relative;
}
#portfolio .portfolio-item .portfolio-item-inner {
position: relative;
}
#portfolio .portfolio-item .portfolio-item-inner .portfolio-info {
opacity: 0;
transition: opacity 400ms;
-webkit-transition: opacity 400ms;
position: absolute;
bottom: 0;
left: 0;
right: 0;
padding: 10px; /*Margin of the text inside the picture of the portfolio item*/
background: rgba(0, 0, 0, 0.5);
color: #fff;
}