html, body { height: 100%; }

body {
  display: -ms-flexbox;
  display: flex;
  -ms-flex-align: center;
  align-items: center;
  padding-top: 40px;
  padding-bottom: 40px;
  background-color: #000;
}

@media (max-width: 767px) {.logo{width:200px;}}

.pulse-button {border: none; -webkit-animation: pulse 1.5s infinite;}

@-webkit-keyframes pulse {
  0% {
    -moz-transform: scale(0.9);
    -ms-transform: scale(0.9);
    -webkit-transform: scale(0.9);
    transform: scale(0.9);
  }
  70% {
    -moz-transform: scale(1);
    -ms-transform: scale(1);
    -webkit-transform: scale(1);
    transform: scale(1);
    box-shadow: 0 0 0 50px rgba(90, 153, 212, 0);
  }
  100% {
    -moz-transform: scale(0.9);
    -ms-transform: scale(0.9);
    -webkit-transform: scale(0.9);
    transform: scale(0.9);
    box-shadow: 0 0 0 0 rgba(90, 153, 212, 0);
  }
}