.video-ul li{
    float: left;
    width: 32.5%;
    margin: 0 1.25% 1.25% 0;
}
.video-ul li:nth-of-type(3n){
    margin: 0 0 1.25% 0;
}
.video-ul p{
    background: #fff;
    color: #333;
    padding: 8% 7.7% 11% 7.7%;
}
.video-img{
    position: relative;
}
.video-img>img{
    width: 100%;
}
.video-img em{
    position: absolute;
    left: 7.7%;
    bottom: 10px;
    width: 36px;
    height: 24px;
    background: url(../images/play.png) no-repeat center;
    background-size: contain;
}
.video-ul li:hover .video-img em{
    background: url(../images/play-act.png) no-repeat center;
    background-size: contain;
}