float

<style>
#float {
text-shadow: -1px 0 #000, 0 1px #000, 1px 0 #000, 0 -1px #000, 0 0;
 font-style: italic;
 font-size:2em;
 font-weight:bold;
 color: #fff;
    animation-name: floating;
    animation-duration: 3s;
    animation-iteration-count: infinite;
    animation-timing-function: ease-in-out;
}

@keyframes floating {
    0% { transform: translate(0,  0px); }
    50%  { transform: translate(0, 15px); }
    100%   { transform: translate(0, -0px); }
}

</style>
<div id="float">floating text</div>