已经声明了documenttype ；
也设置了盒子的宽度，但是就是在屏幕左边
如果给body加text-align：center的话，盒子的最左边边框就在屏幕最中间。
求大佬指jiao
<style>
.new1 {
font-size: 14px;
color: lightcyan;
text-align: center;
}
.div1 {
display: inline-flex;
text-align: center;
height: 52px;
z-index: 999;
top: 0px;
position: fixed;
background-image: linear-gradient(to right,cornflowerblue,green );
width: 1200px;
margin-right:18px;
}
</style>
</head>
<body>
@RenderBody()
@*导航*@
@*<div class="container">*@
<div class="row div1">
<div class="col-lg-2 col-sm-2 co-md-2" style="color: beige; font-size: 18px; margin:7px auto">
鲜花在线销售系统
</div>
<div class="col-lg-1 col-sm-1 col-md-1" style="font-size: 16px; margin:9px auto">
<p onclick="N2()" class="new1">首页</p>
</div>
<div class="col-lg-1 col-sm-1 col-md-1" style="font-size: 15px; margin:9px auto">
<p onclick="N1()" class="new1">在线购买</p>
</div>
<div class="col-lg-1 col-sm-1 col-md-1" style="font-size: 16px; margin:9px auto">
<p onclick="N3()" class="new1">购物车</p>
</div>
<div class="col-lg-3 col-sm-3 col-md-3" style="font-size: 16px; margin:9px auto">
<p>
<input id="Text1" type="text" placeholder="请输入鲜花名称或鲜花用途搜索鲜花~" />
<button style="height:29px; width:54px;">搜索</button>
</p>
</div>
<div class="col-lg-1 col-sm-1 col-md-1" style="font-size: 16px; margin:9px auto">
<p onclick="N4()" class="new1">
鲜花申请
</p>
</div>
<div class="col-lg-1 col-sm-1 col-md-1" style="font-size: 16px; margin:9px auto">
<p onclick="N5()" class="new1">鲜花搭配</p>
</div>
<div class="col-lg-2 col-sm-2 col-md-2" style="font-size: 16px; ">
<img src="../img/13.jpeg" style="border-radius: 50%;overflow: hidden;width: 50px;" onclick="N6()" />
<a href="../Clients/Create" class="new1">注册</a>
<a href="../Clients/Login" class="new1">登录</a>
</div>
</div>
</body>
</html>
