<!DOCTYPE html>
<style>
@keyframes test {
from { background-position: 0 0;}
to { background-position: 1px 1px;}
}
div {
position: absolute;
top: 4em;
width: 400px;
}
.animated {
position: absolute;
animation: test 1000s;
}
</style>
<div>
<span>This sentence shoul</span>
<span class="animated">d span a single line.</span>
</div>