css画圆弧

<template>
    <div class="container">
      <div class="container-bg"></div>  
    </div>
</template>
<script>
export default {
    data() {
        return {
        };
    },
    methods: {
    }
};
</script>

<style>
 .container {
   width: 750rpx;
   height: 100%;
   display: flex;
   flex-direction: column;
   align-items: center;
   background: #F8F8F8;
 }
 .container-bg {
   width: 750rpx;
   height: 346rpx;
   position: relative;
   background-color: #20A0FF;
   position: absolute;
   left: 0;
   top: 0;
   border-radius: 0 0 640rpx 640rpx/0 0 80rpx 80rpx;
 }
</style>