.parent-element {
  display: flex;
  height: 800px;
  border: 0px solid #000;
}

.child-element {
  margin: auto;
}

.f1 {
  font-family: Arial, Helvetica, sans-serif;
  font-weight: bold;
  font-size: 120px;
}

.f2 {
  font-family: Arial, Helvetica, sans-serif;
  font-size: 40px;
}

.f3 {
  font-family: Arial, Helvetica, sans-serif;
  font-size: 21px;
}