h1 {
  text-align: center;
  font-family: Helvetica;
  color: black;
  font-size: 3vw;
}
.center {
  display: block;
  margin-left: auto;
  margin-right: auto;
  width: 50%;
}
.top {
  display: block;
  margin-left: auto;
  margin-right: auto;
  width: 100%;
}