css点击按钮，依次动态展开面板动画效果

<a href="#one">按钮1</a>
<a href="#two">按钮2</a>
<a href='#three'>按钮3</a>
<main>
    <div id="one">所有主流浏览器均支持 :target 选择器，除了 IE8 及更早的版本。</div>
    <div id="two">URL 带有后面跟有锚名称 #，指向文档内某个具体的元素。这个被链接的元素就是目标元素(target element)。</div>
    <div id="three">:target 选择器可用于选取当前活动的目标元素。</div>
</main>

               main{
            display: flex;
            justify-content: flex-start;
        }
        a{
            border: 1px solid #03A9F4;
            padding: 3px 15px;
            border-radius: 7px;
            color: #fff;
            text-decoration: none;
            background: #03A9F4;
        }
        main div{
            width: 100px;
            height: 50px;
            background: pink;
            margin: 5px;
            transition: flex 1s;
            line-height: 50px;
            padding: 10px;
            overflow: hidden;

        }
        div:target{
            flex:;
            background: #8bc34a;
            line-height: normal;
            overflow-y: auto;
        }