为文本添加背景颜色的时间为一秒钟，并有延迟

<style>
    .highlight {
        background-color: yellow;
        animation-name: highlight;
        animation-duration: 1s;
        animation-delay: 1s;
        animation-fill-mode: forwards;
    }

    @keyframes highlight {
        from {
            background-color: transparent;
        }
        to {
            background-color: yellow;
        }
    }
</style>

<script>
    function addHighlight() {
        var text = document.getElementById("text");
        text.classList.add("highlight");
    }

    function removeHighlight() {
        var text = document.getElementById("text");
        text.classList.remove("highlight");
    }

    setTimeout(addHighlight, 1000); // 添加背景颜色的延迟时间为1秒钟
    setTimeout(removeHighlight, 2000); // 移除背景颜色的延迟时间为2秒钟
</script>

<div id="text">这是一段文本。</div>