<style>
    .navbar-brand {
        text-align: center;
        background-image: -webkit-linear-gradient(left, #2d8cf0, #fff 25%, #00bdff 50%, #fff 75%, #2d8cf0);
        -webkit-text-fill-color: transparent;
        -webkit-background-clip: text;
        -webkit-background-size: 200% 100%;
        -webkit-animation: masked-animation 2s infinite linear;

        padding: 15px 15px;
        font-size: 18px;
        line-height: 20px;
        color: #9d9d9d;
    }


    @-webkit-keyframes masked-animation {
        0% {
            background-position: 0 0;
        }
        100% {
            background-position: -100% 0;
        }
    }

</style>
<div style="display: inline-block;padding: 10px 20px;background-color: #999;">
  <span class="navbar-brand">文字效果</span>
</div>

演示