.banner {
    height: 480px;
    text-align: center;
}
.banner img {
    
   height: 100%;
}
.content {
    
 
    text-align: center;

}
.nav-main {
    width: 100%;
    
    height: 50px;
    background-color: #ccc;
}
.nav-main-top {
    position: relative;
}

.nav li {
    height: 50px;
  width: 33%;
    float: left;

    text-align: center;
   
    
    line-height: 50px;
    font-size: 16px;
  box-sizing: border-box;
    
}


.nav li a{
    color: #171717;
}

.nav .active a {
    color: #6790d5;
}
.content h5 {
    padding-top:100px;
    font-size: 25px;
    text-align: center;
}
.content h5 a {
   
    padding-bottom: 5px;
}

.content p {
    margin-top: 20px;
}

.content-main {
    
   padding-top: 30px;
    /* background-color: #ccc; */
}

.content-main #articlelist li img {
    width: 350px;
}
.content-main #articlelist li{
    position: relative;
    margin: 25px;
    height: 400px;
    width: 350px;
    float: left;
}
.content-main #articlelist li h6 {
    font-size: 20px;
    margin-top: 20px;
}