* {
  margin: 0;
  padding: 0;
}

h1 {
  text-align: center;
  padding: 1em;
}

button {
  position: fixed;
  top: 2em;
  left: 2em;
  z-index: 1;
  cursor: pointer;
}

main {
  text-align: center;
  line-height: 2;
}

.drawer {
  position: fixed;
  top: 0;
  bottom: 0;
  left: -100%;
  padding: 4em 0;
  width: 80%;
  max-width: 300px;
  height: 100%;
  background-color: #333;
  box-shadow: 1px 0 4px rgba(0, 0, 0, .3);
  list-style: none;
  transition: all 0.3s ease-in-out;
}

.is-active .drawer{
  left: 0;
}

.drawer a {
  display: block;
  padding: 1em;
  color: #ccc;
  text-decoration: none;
  font-weight: bold;
}

.drawer a:hover {
  background-color: #212121;
  color: #fff;
}