grid.css

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, Helvetica, sans-serif;
    text-decoration: none;
    color: #333;
    z-index: inherit;
}

.row::after {
    content: "";
    clear: both;
    display: table;
}

/* mobile */
[class*="col-"]{
    width: 100%;
    padding: 8px;
    float: left;
}

@media only screen and (min-width: 768px){
    .col-s-1 {width: 8.33%;}
    .col-s-2{width: 16.66%;}
    .col-s-3{width: 25%;}
    .col-s-4{width: 33.33%;}
    .col-s-5{width: 41.66%;}    
    .col-s-6{width: 50%;}
    .col-s-7{width: 58.33%;}
    .col-s-8{width: 66.66%;}
    .col-s-9{width: 75%;}
    .col-s-10{width: 83.33%;}
    .col-s-11{width: 91.66%;}
    .col-s-12{width: 100%;}
}

@media only screen and (min-width: 1024px) {
    .col-1 {width: 8.33%;}
    .col-2{width: 16.66%;}
    .col-3{width: 25%;}
    .col-4{width: 33.33%;}
    .col-5{width: 41.66%;}    
    .col-6{width: 50%;}
    .col-7{width: 58.33%;}
    .col-8{width: 66.66%;}
    .col-9{width: 75%;}
    .col-10{width: 83.33%;}
    .col-11{width: 91.66%;}
    .col-12{width: 100%;}
}