html {
  background: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)),
    url(bg.jpeg) no-repeat center center fixed;
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
  font-family: "Montserrat", sans-serif;
}

.center {
  text-align: center;
  position: absolute;
  color: white;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  margin: 0;
}