style.css

h2 {
  margin-bottom: 50px;
}

.container {
  text-align: center;
  overflow: hidden;
  width: 800px;
  margin: 0 auto;
}

.container table {
  width: 100%;
}

.container td, .container th {
  padding: 10px;
}

.container td:first-child, .container th:first-child {
  padding-left: 20px;
}

.container td:last-child, .container th:last-child {
  padding-right: 20px;
}

.container th {
  border-bottom: 1px solid #ddd;
  position: relative;
  cursor: pointer;
}

.container th.desc:after {
  border-top-color: #666;
}

.container th.asc:before {
  border-bottom-color: #666;
}

.container th:after, .container th:before {
  content: '';
  display: block;
  position: absolute;
  right: 0;
  border-color: transparent;
  border-style: solid;
  border-width: 5px;
  width: 0;
  height: 0;
}

.container th:after {
  border-top-color: #ddd;
  top: 22px;
}

.container th:before {
  border-bottom-color: #ddd;
  top: 10px;
}

.github {
  margin-top: 50px;
}