/* from http://stackoverflow.com/questions/22196587/how-to-center-align-vertically-the-container-in-bootstrap */

.vertical-center {
  min-height: 100%;  /* Fallback for browsers do NOT support vh unit */
  min-height: 100vh; /* These two lines are counted as one :-)       */

  display: flex;
  align-items: center;
}