.topic_capiton {
    position: absolute;
    bottom: 50px;
    left: 6px;
    color: #eee;
    font-size: 54px;
    z-index: 100;
    text-shadow: 2px 2px 2px rgba(0,0,0,0.3);
}

section.banner {
    position: relative;
      background-size:cover;
        background-position:center;
}

    section.banner div:first-child {
        height: 490px;
        width: 100%;
      
        /*background: url(http://webadmin.quanjing.com/Imges/creative/banner/2625122518.jpg) no-repeat;*/
    }

#page_content{
    font-size: 0;
}
#page_content li {
    width: calc(20% - 11px);
    display: inline-flex;
    margin: 5px;
    position: relative;
}
#page_content li img {
    width: 100%;
    height: 100%;
}
#page_content li a {
    width: 100%;
    position: relative;
}
#page_content a video {
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}
@media screen and (max-width: 1366px) {
    #page_content li{
        width: calc(25% - 11px);
    }
}
@media screen and (max-width: 1024px) {
    #page_content li{
         width: calc(33.33% - 11px);
    }
}
@media screen and (max-width: 420px) {
    #page_content li{
         width:100%;
    }
}