巧用背景色实现分隔线：
    .demo_line_02{

    1. 1. height: 1px;
    2. 2. border-top: 1px solid #ddd;
    3. 3. text-align: center;

    }
    .demo_line_02 span{

    1. 1. position: relative;
    2. 2. top: -8px;
    3. 3. background: #fff;
    4. 4. padding: 0 20px;

    }
    优点：代码简洁，可自适应宽度
    inline-block实现分隔线：
    点此查看实例展示
    .demo_line_03{

    1. width:600px;

    }
    .demo_line_03 b{

    1. 1. background: #ddd;
    2. 2. margin-top: 4px;
    3. 3. display: inline-block;
    4. 4. width: 180px;
    5. 5. height: 1px;
    6. 6. _overflow: hidden;
    7. 7. vertical-align: middle;

    }
    .demo_line_03 span{

    1. 1. display: inline-block;
    2. 2. width: 220px;
    3. 3. vertical-align: middle;

    }
    优点：文字可多行