* { margin:0; padding:0; } body { background:#ccc; } .balloon { width:160px; height:160px; border-radius:80px 80px 20px 80px; /* 圆角 左上 右上 右下 左下*/ background:#fff; transform:rotate(45deg); /* 旋转45度*/ box-shadow:-8px -8px 80px -8px #873940 inset; /* 盒子阴影*/ position:absolute; } .balloon::after { /*伪元素*/ content:''; /*激活伪元素*/ position:absolute; bottom:0; right:0; width:0; height:0; border:8px solid transparent; border-right-color:#873940; transform:rotate(45deg); /* 旋转45度*/ border-radius:16px; }