关于移动端1px边框问题

<div class="z_nei_list">
    <div class="z_name_left font-size3">身份证号:</div>
    <div class="z_name_input font-size3">
                <input id="strIdentity" maxlength="18" value="" type="text" placeholder="请输入真实身份证号码" />
    </div>
</div>
<div class="z_nei_lista">
    <div class="z_name_left font-size3">身份证号:</div>
    <div class="z_name_input font-size3">
                <input id="strIdentity" maxlength="18" value="" type="text" placeholder="请输入真实身份证号码" />
    </div>
</div>

　　

.z_nei_list,.z_nei_lista{
    width:94%;
    padding:2% 3% 1% 3%;
    margin:0 auto;
    position: relative;
    background: #fff;
    margin-bottom:8px;
}
 
.z_nei_list:before{
    content: '';
    width:100%;
    height:1px;
    background: #f00;
    position: absolute;
    top:0;
    left:0;
    -moz-transform:scale(1,0.5);
       -webkit-transform:scale(1,0.5);
       -o-transform:scale(1,0.5);
}
.z_nei_lista:before{
    content: '';
    width:100%;
    height:1px;
    background: #f00;
    position: absolute;
    top:0;
    left:0;
    -moz-transform:scale(1,1);
       -webkit-transform:scale(1,1);
       -o-transform:scale(1,1);
}　

.z_nei_list为真正的1像数线，

z_nei_lista为正常情况下1像素线