CSS 전환을 사용하는 트리거 방법은 무엇입니까?

	<style>
		.box{
      		width: 100px;
      		height: 100px;
      		background-color: blueviolet;
      		transition: width 1s linear .5s;
    	}
    	.box:hover{
      		width: 400px;
    	}
	</style>
	<p class="box">
    </p>

<style>
	.box{
      width: 100px;
      height: 100px;
      background-color: blueviolet;
      transition: width 1s linear .5s;
    }
    .box1{
      width: 400px;
    }</style>
<p class="box">    
</p>

<scrpit>
	setTimeout(() => {
      let element = document.getElementsByClassName(&#39;box&#39;)[0];
      element.classList.add(&#39;box1&#39;)
    }, 1) </scrpit>