page.css

h1 {
  padding: 0;
  margin: 0;
}

.article {
  padding: 10px;
  border: 1px solid hsl(0, 30%, 55%);
  margin-bottom: 10px;
}

.article .header {
  border-bottom: 2px solid black;
  width: 50%;
}

.highlight {
  border: 5px solid hsl(0, 30%, 55%);
}

.advertisement {
  padding: 10px;
  background-color: #aaa;
  margin-bottom: 10px;
}

#content {
  width: 50%;
  margin-left: auto;
  margin-right: auto;
}