hr {
  width: 80%
}

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

h1 {
  text-align: center
}

tt {
  font-family: Courier, monospace
}

p.duedate {
  text-align: center;
  font-weight: bold
}

blockquote.code {
  font-family: Courier, monospace
}

ol.probs li {
  margin-bottom: 2em
}

ul.probs li {
  margin-bottom: 2em
}

table.example {
  margin-left: auto;
  margin-right: auto
}

table.example td {
  padding-left: 1em;
  padding-right: 1em
}

div.bigsym {
  font-size: xx-large
}