LayoutTests/fast/animation/starting-style-repeat.html

<style>
div { transition: color 10s step-end; display: none; color: red; }
.show { display: block; }
@starting-style {
    div { color: green; }
}
</style>
<div id=t>This should be green.</div>
<script>
t.offsetHeight;
t.classList.add("show");
t.offsetHeight;
t.classList.remove("show");
t.offsetHeight;
t.classList.add("show");
</script>