<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style>
span{
display: block;
width: 0;
height: 0;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
border-bottom: 100px solid red;
}
</style>
</head>
<body>
<span></span>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style>
span{
display: block;
width: 0;
height: 0;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
border-bottom: 100px solid red;
border-bottom-left-radius: 100px;
border-bottom-right-radius: 100px;
}
</style>
</head>
<body>
<span></span>
<script src="./jquery-3.5.0/jquery-3.5.0.min.js"</script>
<script>
</script>
</body>
</html>