body {
  background-color: #FFFFFFF;
  color: black;
}

.vertical-container {
  height: 300px;
  display: -webkit-flex;
  display:         flex;
  -webkit-align-items: center;
          align-items: center;
  -webkit-justify-content: center;
          justify-content: center;
}

h1.vertical-container {
  font-size: 275%;
}