.nav > li:nth-of-type(3) a {
  color: #2a4f82;
  text-decoration: underline;
  }
.img{
  width:100%;
  position: relative;
  overflow: hidden;

}
.img > img{
  display: block;
}
#content{
  width: 100%;
  height: 780px;
  background: #fff;
  overflow:hidden;
}
#content > img{
  margin-top: 50px;
}