<div class="messageContainer">
  <p class="message"></p>
</div>

.messageContainer {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translateX(-50%) translateY(-50%);
  width: 50ch;
  min-height: 50vh;
  padding: 1em;
  
  background-color: #dddddd;
  opacity: 0;
  transition: opacity 2000ms ease-in-out;
  transition-delay: 500ms;
}

.messageContainer.visible {
  opacity: 1;
}

.message {
  text-align: center;
  line-height: 50vh;
}

.fade-in-out {
  animation: fade-in-out;
  animation-duration: 2500ms;
}

@keyframes fade-in-out {
  0%, 100% {
    opacity: 0;
  }
  50% {
    opacity: 1;
  }
}

const messages = [
  'Hello, welcome to my tutorial',
	'It seems you\'re new here',
	'Don\'t forget to sign up to my mailing list',
]

let msg = document.querySelector('.message');

//Load in initial container
document.querySelector('.messageContainer').classList.add('visible');

//start sequence
setTimeout(changeMessage.bind(null, 0), 2500);

function changeMessage(index) {
	if (index >= messages.length) { return; }
  
  msg.classList.remove('fade-in-out');
  msg.textContent = messages[index];
  
  //Trigger reflow so page re-calculates itself
  //and doesn't optimize away the adding and
  //removing of the same class
  void msg.offsetWidth;
  
  msg.classList.add('fade-in-out');
  setTimeout(changeMessage.bind(null, index + 1), 2500);
}