* {
    box-sizing: border-box;
}

body {
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    background-color: #fff;

}

.container {
    border: 1px dotted red;
}

.col {
    float: left;
    padding: 0 15px;

}

.clearfix::before ,
.clearfix::after {
    content: " ";
    display: table;
}

.clearfix::after{
    clear: both;
}

@media (min-width: 768px){
    .container {
      width: 750px;
      margin: 0 auto;
    }

    .col {
        width: 50%;
    }

    section .col:nth-of-type(2n+1){
        clear: both;
    }
}

@media (min-width: 992px){
    .container {
        width: 970px;
    }

    .col {
        width: 33.33%;
    }

     section .col:nth-of-type(2n+1){
        clear:none;
    }

    section .col:nth-of-type(3n+1){
        clear: both;
    }
}

@media (min-width: 1200px) {
    .container {
        width: 1170px;
    }
    .col {
        width: 25%;
    }
 section .col:nth-of-type(2n+1){
        clear: none;
    }

    section .col:nth-of-type(3n+1){
        clear: none;
    }

    section .col:nth-last-of-type(4n+1){
        clear: both;
    }
}