我遇到了一個codepen示例，它允許我遍歷各種div元素(鏈接到示例。我想在清單上增加更多的項目。我添加了額外的div，并給了它們受人尊敬的類名序列號，但是它們沒有出現(xiàn)。我還在下面列出了HTML和CSS代碼。

你知道為什么嗎？

<h1>
  <span>always be</span>
  <div class="message">
    <div class="word1">close</div>
    <div class="word2">code</div>
    <div class="word3">creating</div>
    <div class="word4">times</div>
  </div>
</h1>

* {
  box-sizing: border-box;
}

body {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  width: 100vw;
}
h1 {
  color: #333;
  font-family: tahoma;
  font-size: 3rem;
  font-weight: 100;
  line-height: 1.5;
  text-transform: uppercase;
  white-space: nowrap;
  overflow: hidden;
  position: relative;
  width: 550px;
}

h1 span {
  font-size: 40px;
  margin-left: 40px;
}

.message {
  background-color: yellow;
  color: #333;
  display: block;
  font-weight: 900;
  overflow: hidden;
  position: absolute;
  padding-left: 0.5rem;
  top: 0.2rem;
  left: 270px;
  animation: openclose 5s ease-in-out infinite;
}

.word1, .word2, .word3 {
  font-family: tahoma;
}

@keyframes openclose {
  0% {
    top: 0.2rem;
    width: 0;
  }
  5% {
    width: 0;
  }
  15% {
    width: 230px;
  }
  30% {
    top: 0.2rem;
    width: 230px;
  }
  33% {
    top: 0.2rem;
    width: 0;
  }
  35% {
    top: 0.2rem;
    width: 0;
  }
  38% {
    top: -4.5rem;
    
  }
  48% {
    top: -4.5rem;
    width: 190px;
  }
  62% {
    top: -4.5rem;
    width: 190px;
  }
  66% {
    top: -4.5rem;
    width: 0;
    text-indent: 0;
  }
  71% {
    top: -9rem;
    width: 0;
    text-indent: 5px;
  }
  86% {
    top: -9rem;
    width: 285px;
  }
  95% {
    top: -9rem;
    width: 285px;
  }
  98% {
    top: -9rem;
    width: 0;
    text-indent: 5px;
  }
  100% {
    top: 0;
    width: 0;
    text-indent: 0;
  }
}