* {
  box-sizing: border-box;
}

body {font-family: Arial, Helvetica, sans-serif ;}

.header {
  border: 2px solid red;
  padding: 15px;
  font-size: 15pt;
}


.min {min-width: 320px;}

div {padding: 15px
     min-width: 600px;
}


img {
    max-width: 100%;
    height: auto;
}


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

[class*="col-"] {
  float: left;
  padding: 15px;
  # border: 1px solid red;
}

.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%;}