* {
    box-sizing: border-box;
}

body {
  margin-left: 25%;
  margin-right: 25%;
}

img {
  display: block;
  margin-left: auto;
  margin-right: auto;
  width: 300px;
  height: auto;
}

.column.a {
  float: left;
  width: 50%;
  padding-right: 50px;
}

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

hr.half {
  width: 50%;
}


@media screen and (max-width: 900px) {

  body{
    margin: 0px;
    padding: 10px;
  }
  .column.a {
    width: 100%;
    padding: 10px;
  }
  .img {
    width: 100%;
    height: auto;
  }
}