body {

  font: 18px/1.5 sans-serif;

}

​

aside {

  height: 200px;

  width: 100px;

  padding: 20px 10px;

  box-sizing: border-box;

  background: #000;

  color: #fff;

  float: left;

  opacity: 0.4

}

​

main {

  padding: 30px;

  background: #ccc;

}