style.css

* {
  box-sizing: border-box;
}

.topnav {
  overflow: hidden;
  background-color: #333;
}

.topnav a {
  float: left;
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 17px;
}

.topnav a:hover {
  background-color: #ddd;
  color: black;
}

.topnav a.active {
  background-color: #04AA6D;
  color: white;
}

.flex-container {
  padding: 0;
  margin: 0;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: center;
}

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

.flex-item {
  width: 51%;
  align-items: center;
  justify-content: center;
}

[class*="col-"] {
  float: left;
}

.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%;}

.config-text {
  margin-top: 5px;
  margin-bottom: 5px;
}

.property {
  border-style: solid;
  border-width: 1px;
  border-color: black;
  background-color: #c9c6c5;
  margin: 3px;
  justify-content: center;
  height: auto;
  flex: 1;
}

a.button {
  padding: 1px 6px;
  border: 1px outset buttonborder;
  border-radius: 3px;
  color: buttontext;
  background-color: buttonface;
  text-decoration: none;
}

.mapping {
  border: 1px solid black;
  border-collapse: collapse;
}

.btn{
  display: inline-block;
  padding: 6px 12px;
  margin-bottom: 5px;
  margin-top: 5px;
  font-size: 14px;
  font-weight: 400;
  line-height: 1.42857143;
  text-align: center;
  white-space: nowrap;
  vertical-align: middle;
  -ms-touch-action: manipulation;
  touch-action: manipulation;
  cursor: pointer;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  background-image: none;
  border: 1px solid transparent;
  border-radius: 4px;
  text-decoration: none;

  color: #333;
  background-color: #fff;
  border-color: #ccc;
}

a {
  color: blue;
}