nav2 {display:block;background:#f2f2f2;padding:20px}
nav2 h2 {display:block;float:left;color:#2b2b2b;text-decoration:none;margin:0;padding:0}
nav2 ul {display:block;float:right;list-style:none;margin:0;padding:0;margin-top:5px}
nav2 ul li {display:block;float:left;margin-left:20px}
nav2 ul li a {color:#5ba9e2;text-decoration:none}
nav2 ul li a:hover {text-decoration:underline}
.video-back {display:block;padding:250px 0;text-align:center;width: 100%;margin: 0 auto;position: relative;overflow: hidden;z-index: 0;height:100vh;}
.video-back h1 {display:block;text-align:center;color:#fff;padding-top: 8.5rem;font-size: 2.8rem;letter-spacing: 2px;}
.video-back p {display:block;color:#fff;margin:0;font-size: 1.2rem;padding:0;margin-bottom: 1.25rem;}
.video-back img {width:150px}
.main-heading {text-align:center;margin:50px auto;font-size:70px}
.main-para {margin:10px 100px;text-align:center;font-size:20px}
.jq22-demo a {color:#f0f8ff;font-family:微软雅黑;font-size:20px;text-decoration:none;padding-left:10px;padding-right:10px;font-weight:700;text-shadow:2px 2px 4px #000}