响应式布局实例操作

*{
    margin: 0px;
    padding: 0px;
}

.heading,
.container,
.footing{
    margin: 10px auto;
}
.heading{
    height: 100px;
    background-color: chocolate;
}
.left,
.right,
.main{
    background-color: cornflowerblue;
}

.footing{
    height: 100px;
    background-color: aquamarine;
}

@media screen and (min-width: 960px){
    .heading,
    .container,
    .footing{
        width: 960px;
    }

    .left,
    .main,
    .right{
        float: left;
        height: 500px;
    }

    .left,
    .right
    {
        width: 200px;
    }
    .main{
        margin-left: 5px;
        margin-right: 5px;
        width: 550px;
    }
    .container{
        height: 500px;
    }

}

@media screen and (min-width: 600px) and (max-width: 960px){
    .heading,
    .container,
    .footing{
        width: 600px;
    }

    .left,
    .main
    {
        float: left;
        height: 400px;
    }
    .right{
        display: none;
    }
    .left{
        width: 160px;
    }
    .main{
        width: 435px;
        margin-left: 5px;
    }
    .container{
        height: 400px;
    }
}

@media screen and (max-width: 600px){
    .heading,
    .container,
    .footing{
        width: 400px;
    }

    .left,
    .right{
        width: 400px;
        height: 100px;
    }
    .main{
        margin-top: 10px;
        width: 400px;
        height: 200px;
    }
    .right{
        margin-top: 10px;
    }
    .container{
        height: 420px;
    }
}