用html实现一个动态的文字框

<!DOCTYPE html>
<html lang="en" >
<head>
  <meta charset="UTF-8">
  <title>一个动态的文字框动画</title>
  <link rel="stylesheet" href="./style.css">

</head>
<body>
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Lato">
<div class="content">
  <div class="content_container">
    <p class="content_container_text">
      Hello
    </p>

    <ul class="content_container_list">
      <li class="content_container_list_item">world !</li>
      <li class="content_container_list_item">friend !</li>
      <li class="content_container_list_item">users !</li>
      <li class="content_container_list_item">everybody !</li>
    </ul>
  </div>
</div>
</body>
</html>

body {
    width: 100%;
    height: 100%;
    position: fixed;
    background-color: #5e3434;
}

.content {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    height: 160px;
    overflow: hidden;
    font-family: "Lato", sans-serif;
    font-size: 35px;
    line-height: 40px;
    color: #fff;
}

.content_container {
    font-weight: 600;
    overflow: hidden;
    height: 40px;
    padding: 0 40px;
}

.content_container:before {
    content: "[";
    left: 0;
}

.content_container:after {
    content: "]";
    position: absolute;
    right: 0;
}

.content_container:before, .content_container:after {
    position: absolute;
    top: 0;
    color: #a04d16;
    font-size: 42px;
    line-height: 40px;
    -webkit-animation-name: opacity;
            animation-name: opacity;
    -webkit-animation-duration: 2s;
            animation-duration: 2s;
    -webkit-animation-iteration-count: infinite;
            animation-iteration-count: infinite;
}

.content_container_text {
    display: inline;
    float: left;
    margin: 0;
}

.content_container_list {
    margin-top: 0;
    padding-left: 110px;
    text-align: left;
    list-style: none;
    -webkit-animation-name: change;
            animation-name: change;
    -webkit-animation-duration: 10s;
            animation-duration: 10s;
    -webkit-animation-iteration-count: infinite;
            animation-iteration-count: infinite;
}

.content_container_list_item {
    line-height: 40px;
    margin: 0;
}

@-webkit-keyframes opacity {
    0%, 100% {
        opacity: 0;
    }

    50% {
        opacity: 1;
    }
}

@keyframes opacity {
    0%, 100% {
        opacity: 0;
    }

    50% {
        opacity: 1;
    }
}

@-webkit-keyframes change {
    0%, 12.66%, 100% {
        transform: translate3d(0, 0, 0);
    }

    16.66%, 29.32% {
        transform: translate3d(0, -25%, 0);
    }

    33.32%, 45.98% {
        transform: translate3d(0, -50%, 0);
    }

    49.98%, 62.64% {
        transform: translate3d(0, -75%, 0);
    }

    66.64%, 79.3% {
        transform: translate3d(0, -50%, 0);
    }

    83.3%, 95.96% {
        transform: translate3d(0, -25%, 0);
    }
}

@keyframes change {
    0%, 12.66%, 100% {
        transform: translate3d(0, 0, 0);
    }

    16.66%, 29.32% {
        transform: translate3d(0, -25%, 0);
    }

    33.32%, 45.98% {
        transform: translate3d(0, -50%, 0);
    }

    49.98%, 62.64% {
        transform: translate3d(0, -75%, 0);
    }

    66.64%, 79.3% {
        transform: translate3d(0, -50%, 0);
    }

    83.3%, 95.96% {
        transform: translate3d(0, -25%, 0);
    }
}