/*内容*/
.substance{ width:1200px; height:auto;position: relative; margin: 0 auto;  clear: both;
   background-image: url()}



.substance h2{ text-align: center; margin-top: 30px; position:relative} 
.substance hr{ width: 420px; height: 2px; background:black; text-align: center; margin-top: 62px;
 position:absolute;left: 380px;}

.substance .mid{ width: 1200px; height: 900px; margin: 0 auto;}
.substance .mid .img{ margin-top: 20px;margin-left: 30px; position: relative;}

.substance .mid .content{ margin-top: 40px; width: 1100px; margin-left: 50px; position: relative;}
.substance .mid .content p{ margin-top: 50px; line-height: 30px;}