一个内凹优惠券样式

效果如下

<template>
  <div class="coupon-box">
    <div class="l">
      <div class="p1">
        <slot name="left"></slot>
      </div>
      <div class="p2">
        <div class="top"></div>
        <div class="bottom"></div>
      </div>
    </div>
    <div class="r">
      <div class="p1">
        <div class="top"></div>
        <div class="bottom"></div>
      </div>
      <div class="p2">
        <slot name="right"></slot>
      </div>
    </div>
  </div>
</template>

<script>
export default {
};
</script>

<style lang="less" scoped>
  .coupon-box {
    @themeColor: #4286F5;
    @themeColorDisabled: #ADAFB4;
    @roundWidth: 10px;

    width: 92%;
    height: 115px;
    display: flex;
    .l {
      width: 104px;
      height: 100%;
      display: flex;
      .p1, .p2 {
        background-color: @themeColor;
      }
      .p1 {
        width: 94px;
        height: 100%;
        border-radius: 4px 0 0 4px;
        box-shadow: 0px 0px 12px 0px rgba(0,0,0,0.08);
      }
      .p2 {
        width: calc(@roundWidth + 1px);
        height: calc(100% - @roundWidth * 2);
        margin-top: auto;
        margin-bottom: auto;
        position: relative;
        margin-left: -1px;
      }
      .top, .bottom {
        width: calc(@roundWidth + 1px);
        height: 60px;
        background-size: 10px 60px;
        background-repeat: no-repeat;
        position: absolute;
        right: 0;
      }
      .top {
        background: radial-gradient(circle at right 0px, transparent 10px, @themeColor 10px);
        background-position: right top;
        top: -@roundWidth;
      }
      .bottom {
        background: radial-gradient(circle at right bottom, transparent 10px, @themeColor 10px);
        background-position: right bottom;
        bottom: -@roundWidth;
      }
    }

    .r {
      width: calc(100% - 104px);
      height: 100%;
      position: relative;
      display: flex;
      .p1, .p2 {
        background-color: #fff;
      }
      .p1 {
        width: calc(@roundWidth + 1px);
        height: calc(100% - @roundWidth * 2);
        margin-top: auto;
        margin-bottom: auto;
        position: relative;
      }
      .p2 {
        width: calc(100% - @roundWidth);
        height: 100%;
        border-radius: 0 4px 4px 0;
        box-shadow: 0px 0px 12px 0px rgba(0,0,0,0.08);
      }
      .top, .bottom {
        width: calc(@roundWidth + 2px);
        height: 60px;
        background-size: 10px 60px;
        background-repeat: no-repeat;
        position: absolute;
        left: 0;
      }
      .top {
        background: radial-gradient(circle at left 0px, transparent 10px, #fff 10px);
        background-position: left top;
        top: -@roundWidth;
      }
      .bottom {
        background: radial-gradient(circle at left bottom, transparent 10px, #fff 10px);
        background-position: left bottom;
        bottom: -@roundWidth;
      }
    }
  }
</style>

最大难点在这里

既需要内凹又要透明，券整体还要有box-shadow
并且手机上div间还会可能有莫名的连接缝隙

试过伪类、纯radial-gradient + linear-gradient都不理想
看了好几个已有实现都不满足，比如
https://codepen.io/Ariex/pen/...
https://codepen.io/mudontire/...