微信小程序 div选中效果

._left{
    position: relative; 
    margin-top: 40rpx;
    width: 40%;
    height: 350rpx;
    border-radius: 12rpx;
    text-align: center;
    font-size: 26rpx;
    background-color: #FCF2D7;
    color: #9F7F43;
    border: 2rpx solid #FFC11B;
   }

._left:before{ 
  content: '';
  display: inline-block;
  position: absolute;
  right: 0;
  top: 0;
  width: 0;
  height: 0;
  border-top: 28px solid #FBCF6B; 
  border-left: 28px solid transparent; 

  } 
._left:after{ 
    content: '';
    position: absolute;
    right: 1px;
    top: 5px;
    width: 8px;
    height: 4px;
    display: inline-block;
    border: 1px solid #fff;
    border-width: 0 0 1px 1px;
    transform: rotate(-45deg);
    -ms-transform: rotate(-45deg);
    -moz-transform: rotate(-45deg);
    -webkit-transform: rotate(-45deg);
    -o-transform: rotate(-45deg);
    vertical-align: baseline; 
  }