body {
  background-image: url('background1.png');
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-size: cover;
}

.flex-container {
  display: flex;
  justify-content: center;
  height: 850px;
  align-items: stretch;
}

.flex-container > div {
  border-style: solid;
  border-width: 5px;
  border-color: black;
  background-image: linear-gradient(to bottom, rgba(26,222,255,0.8), rgba(0,94,184,0.9));
  color: white;
  margin: 10px;
  text-align: center;
  line-height: 75px;
  font-size: 30px;

}

.center {
  display: block;
  margin-left: auto;
  margin-right: auto;
  width: 80%;
}