新人求助，扫码button在电脑调试正常，在手机上button被地图覆盖了，求高手指点。

index.wxml:

<view class='container'>

<view class='search'>

<input placeholder='请输入关键字搜索' confirm-type='search' ></input>  

</view>

<view class='mapcontainer'>

<map id='map' longitude='{{longitude}}' latitude='{{latitude}}'  scale='14' show-location style='width:100%;height:550px;'></map>  

</view>

<view class='buttonQr'>

<button size='mini' plain='true' bindtap='btnQrClick'>扫码</button>

</view>  

</view>

index.wxss:

/**index.wxss**/

.container{

display: flex;

background-color: transparent;

}

.search{

border: 1px inset #8e2323;

width: 60%;

height: 20%;

left: 20%;

background-color: transparent;

}

.mapcontainer{

width:100%;

height:100%;

z-index: 4;

}

.buttonQr{

border: 1px;

position: absolute;

left: 0px;

top:0px;

z-index:5;

}