/*使屏幕变暗  */
.background_screen {
    width: 100%;
    height: 100%;
    position: fixed;
    top: 0;
    left: 0;
    background: #000;
    opacity: 0.4;
    overflow: hidden;
    z-index: 99;
    color: #fff;
}

/*对话框 */
.attr_box {
    width: 100%;
    max-height: 80vh;
    position: fixed;
    bottom: 0;
    left: 0;
    z-index: 99;
    border-radius: 40px 40px 0 0;
    border-radius: 40px 40px 0px 0px;
    border-top-left-radius: 30rpx;
    border-top-right-radius: 30rpx;
    box-sizing: border-box;
    /*兼容 IOS<11.2*/
    // padding-bottom: constant(safe-area-inset-bottom);
    /*兼容 IOS>11.2*/
    // padding-bottom: env(safe-area-inset-bottom);
}