div 背景图片，适配变形，可以用边框形式

border: 1.5625vw solid transparent;
    border-top- 3vw;
    border-left- 1vw;
    border-right- 1vw;
    border-bottom- 3vw;
    border-color: transparent;
    position: relative;
    border-image-source: url(img/card_bg.24a12478.png);
    border-image-slice: 70 20 70 20 fill;
    border-image-outset: 0px;
    border-image-repeat: stretch repeat;

　　内容高度 设置为 calc(100% + 4vw)