body {
  margin: 0;
  padding: 5vh 5vw;
  background: black;
  overflow:hidden;
}

* {
  box-sizing: border-box;
}

p {
  font-family: monospace;
  font-weight: bold;
  font-size: 4.1vh;
  margin: 0;
  padding: 0;
  line-height: 1;
  color: limegreen;
  text-shadow: 0px 0px 10px limegreen;
}

.msg {
  font-family: monospace;
  font-weight: bold;
  text-transform: uppercase;
  font-size: 5vh;
  padding-top: 5vh;
  background: red;
  box-shadow: 0 0 30px red;
  text-shadow: 0 0 20px white;
  color: white;
  width: 20vw;
  height: 15vh;
  position: absolute;
  left: 50%;
  margin-left: -10vw;
  top: 50%;
  margin-top: -5vh;
  text-align: center;
  min-width: 200px;
  animation-name: blink;
  animation-duration: 0.6s;
  animation-iteration-count: infinite;
  animation-direction: alternate;
  animation-timing-function: linear;
}

@keyframes blink {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}