SOURCE

var words = document.querySelectorAll(".word");
words.forEach(function (word) {
  var letters = word.textContent.split("");
  word.textContent = "";
  letters.forEach(function (letter) {
    var span = document.createElement("span");
    span.textContent = letter;
    span.className = "letter";
    word.append(span);
  });
});
var currentWordIndex = 0;
var maxWordIndex = words.length - 1;
words[currentWordIndex].style.opacity = "1";
var rotateText = function () {
  var currentWord = words[currentWordIndex];
  var nextWord = currentWordIndex === maxWordIndex ? words[0] : words[currentWordIndex + 1];
  // rotate out letters of current word
  Array.from(currentWord.children).forEach(function (letter, i) {
    setTimeout(function () {
      letter.className = "letter out";
    }, i * 80);
  });
  // reveal and rotate in letters of next word
  nextWord.style.opacity = "1";
  Array.from(nextWord.children).forEach(function (letter, i) {
    letter.className = "letter behind";
    setTimeout(function () {
      letter.className = "letter in";
    }, 340 + i * 80);
  });
  currentWordIndex =
  currentWordIndex === maxWordIndex ? 0 : currentWordIndex + 1;
};
rotateText();
setInterval(rotateText, 4000);

<div class="rotating-text">
  <p>CSS Animation is</p>
  <p>
    <span class="word alizarin">生成中.</span>
    <span class="word wisteria">生成中.</span>
    <span class="word peter-river">生成中.</span>
    <span class="word emerald">生成中.</span>
    <span class="word sun-flower">生成中.</span>
  </p>
</div>

@import url(https://fonts.googleapis.com/css?family=Lato:600);
body {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  background: #222;
}

.rotating-text {
  font-family: Lato, sans-serif;
  font-weight: 600;
  font-size: 36px;
  color: white;
  transform: translateX(-80px);
}
.rotating-text p {
  display: inline-flex;
  margin: 0;
  vertical-align: top;
}
.rotating-text p .word {
  position: absolute;
  display: flex;
  opacity: 0;
}
.rotating-text p .word .letter {
  transform-origin: center center 25px;
}
.rotating-text p .word .letter.out {
  transform: rotateX(90deg);
  transition: 0.32s cubic-bezier(0.6, 0, 0.7, 0.2);
}
.rotating-text p .word .letter.in {
  transition: 0.38s ease;
}
.rotating-text p .word .letter.behind {
  transform: rotateX(-90deg);
}

.alizarin {
  color: #e74c3c;
}

.wisteria {
  color: #8e44ad;
}

.peter-river {
  color: #3498db;
}

.emerald {
  color: #2ecc71;
}

.sun-flower {
  color: #f1c40f;
}