css 三角

<style>
        .test{
            width: 0px;
            height: 0px;
            
            border: 50px solid red;
            border: 50px solid black;
            /* border-top-width: 50px;
            border-top-style: solid;
            border-top-color: black; */
            border-color: black orange yellow green;
            border-color: black transparent transparent transparent ;<-隐藏->
        }
    </style>