我希望有人帮我在 [border-bottom: 3px solid #a3c846;] 下方放置一个彩色动画进度条，例如随着变量 [timer] 的时间变慢，有人能帮我吗？谢谢！
$(document).ready(function(){
window.addEventListener("message",function(event){
var html = "<div id='"+event.data.css+"'>"+event["data"]["mensagem"]+"</div>"
$(html).fadeIn(500).appendTo("#notifications").delay(event["data"]["timer"]).fadeOut(500);
})
});#sucesso {
background: rgba(34,34,34,0.75) url("images/check.png") no-repeat center left 11px;
border-bottom: 3px solid #a3c846;
}<html>
<head>
<meta charset="UTF-8">
<title>#creative</title>
<script src="nui://game/ui/jquery.js"></script>
<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.min.js" integrity="sha256-VazP97ZCwtekAsvgPBSUwPFKdrwD3unUfSGVYrahUqU=" crossorigin="anonymous"></script>
<link href="https://fonts.googleapis.com/css2?family=Roboto&display=swap" rel="stylesheet">
<link rel="stylesheet" href="style.css">
</head>
<body>
<div id="notifications">
</div>
<script src="app.js"></script>
</body>
</html>