@media only screen and (max-width: 1300px){

    .box ul{
        width: 700px;
        margin: 0 auto;
    }

    .content-title{
        font-size: 16px;
    }

    .firstText, .secondText, 
    .thirdText, .fourthText, 
    .fifthText, .sixthText {
        width: auto;

    }

}

@media only screen and (max-width: 900px){

    .box ul{
        width: 90%;
    }

}

@media only screen and (max-width: 650px){

    .box ul{
        width: 95%;
    }

    .content-title{
        font-size: 15px;
    }

    .firstText, .secondText, 
    .thirdText, .fourthText, 
    .fifthText, .sixthText {
        font-size: 13px;
    }
}

@media only screen and (max-width: 400px){

    .box ul{
        width: 100%;
    }

    .visible{
        margin-left: 20px;
        margin-right: 20px;
    }

}