.topbar{
  display: flex;
  flex-flow: row nowrap;
  justify-content: space-between;
  align-items: center;
  position: fixed;
  width: calc(100% - 10px);
  left: 0;
  top:0;
  z-index: 999;
  height: 45px;
  padding: 0 5px;
  background-color: #fff;
  box-shadow: 1px 1px 1px #ddd;
}
.topbar-title{
  color: #27342B;
  font-weight: 600;
}
.topbar-back:active{
  opacity: 0.7;
}

以下以微信小程序为例，当然也可以自行改为HTML5代码

<view class="topbar">
  <view class="topbar-back" bindtap="goBack">返回</view>
  <view class="topbar-title">管理端</view>
  <view class="topbar-right">搜索</view>
</view>