html, body {
  height: 100%;
  background: linear-gradient(to right, #336699, #00cc99);
  background-size: cover;
  background-position: center;
  animation: animatedBackground 10s linear infinite;
}
.container {
  height: 100%;
}

.card {
  margin-top: -100px; /* set negative margin to vertically center card */
  background: rgba(255, 255, 255, 0.8);
}

.logo {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  border: 5px solid #fff;
  margin: 0 auto;
  margin-bottom: 10px;
}