.parallax_demo-b {
        height: 3000px;
        position: relative;
        background: url(https://www.transparenttextures.com/patterns/batthern.png);
        overflow: hidden;
    }
    .parallax_demo-ttl {
        padding: 10px 15px;
        background-color: #07355a;
        color: #fff;
        position: relative;
        z-index: 100;
        font-size: 24px;
    }
    .parallax_demo-ttl span {
        display: block;
        width: 100%;
        max-width: 1400px;
        margin: 0 auto;
    }
    .chain {
        width: 50px;
        height: 100%;
        position: absolute;
        top: 0;
        left: 3%;
    }
    .chain:before {
        display: block;
        position: absolute;
        top: 0;
        right: 0;
        left: 0;
        width: 1px;
        height: 100%;
        margin: auto;
        background-color: #999;
        content: '';
    }
    .obj {
        width: 50px;
        height: 50px;
        border-radius: 50%;
        border: solid 1px #fff;
        position: absolute;
        top: 400px;
        left: 0;
        background-color: #999;
    }

    /* chain_02 */
    .chain_02 {
        width: 150px;
        left: 30%;
    }
    .chain_02:before {
        width: 5px;
        background-color: #666;
    }
    .chain_02 .obj {
        width: 150px;
        height: 150px;
        background-color: #666;
    }

    /* chain_03 */
    .chain_03 {
        width: 300px;
        left: 20%;
    }
    .chain_03:before{
        width: 10px;
        background-color: #333;
    }
    .chain_03 .obj {
        top: 1000px;
        width: 300px;
        height: 300px;
        background-color: #333;
    }

    /* chain_04 */
    .chain_04 {
        width: 600px;
        left: 5%;
    }
    .chain_04:before{
        width: 20px;
        background-color: #000;
    }
    .chain_04 .obj {
        top: 2000px;
        width: 600px;
        height: 600px;
        background-color: #000;
    }