body, html {
  margin: 0;
}
canvas {
  display: block;
}
a {
  font-family: 'Montserrat', sans-serif;
  font-size: 30px;
  position: absolute;
  top: calc(50% - 25px);
  left: calc(50% - 150px);
  width: 300px;
  height: 50px;
  line-height: 50px;
  box-sizing: border-box;
  text-align: center;
  text-decoration: none;
  background-color: rgba(0, 0, 0, 0.5);
  color: #fff;
  border: 1px solid #fff;
  border-radius: 50px;
}