.picker_mask{
    width: 100%;
    top: 3.24rem;
    height: calc(100% - 3.24rem);
    background: rgba(0,0,0,.6);
    position: fixed;
    left: 0;
    z-index:100;
    display: none;
}
.picker {
    background: #fff;
    max-height:70%;
    overflow-y:auto;
}
.picker li{
    height: 60px;
    line-height: 60px;
    padding: 0 20px;
    color: #aaa;
    cursor: pointer;
}
.picker li.choose{
    background: #f8f8fa;
}