答案 0 :(得分:2)
请试试这个:
.container {
background: yellow;
height: 180px;
width: 400px;
}
.box {
width:400px;
height:80px;
background-color: white;
border:1px solid white;
border-width:0 0 13px 0;
margin:1rem auto;
-webkit-border-radius:0% 0% 50% 50% / 0% 0% 50% 50%;
-moz-border-radius:0% 0% 50% 50% / 0% 0% 50% 50%;
border-radius:0% 0% 50% 50% / 0% 0% 50% 50%;
}
<div class="container"><div class="box"></div></div>