.dumb {
    border-radius: 10px;
    height:100px;
    background-color:gainsboro;

}
.row{
    display:flex;
    width:100%;
    background-color: gainsboro
}
.row::after{
    display: block;
    clear:both;
    content: "";
}
.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%;}
*{
    box-sizing: :border-box;
}
[class*= "col-"]{
    padding: px;

}
h1{
    text-align: center;
    color: limegreen;
    background-color:grey;
   margin:1px;
    display:block;
}
h2{
    text-align: center;
}