body {
  background: black;
  font-family: Avenir;
  color: rgb(128, 128, 128);
}

.button {
  background-color: rgb(100, 100, 100);
  border-style: solid;
  border-width: 2px;
  border-color: rgb(173, 173, 173);
  color: black;
  padding: 20px 70px;
  text-align: center;
  text-decoration: none;
  display: inline-block;
  font-size: 16px;
  border-radius: 8%;
  margin: 10px;
}

.center {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 6px;
}

.btn-group {
  display: flex;
  flex-direction: column;
}

.link {
  text-decoration: none;
  color: inherit;
}