高手看下，想让内容框变大，然后文字居中浮动，但是一直无法实现，麻烦帮我看下！谢谢
<%@ Page Language="C#" MasterPageFile="~/MasterPage.Master" AutoEventWireup="true"
    CodeBehind="StudentDefault.aspx.cs" Inherits="ProjectAnswer.StudentDefault" Title="无标题页" %>

<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
    <style type="text/css">
        # container
        {
            width: 900px;
            height: 390px;
            background-color: Lavender;
            float: none;
            margin-top: 0px;
            margin-bottom: 0px;
            margin-left: auto;
            margin-right: auto;
            lin-height: 390px;
            overflow: hidden:;
        }
    </style>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
    <div id="container:">
        <marquee><font size="6">欢迎进入界面</font><br /></marquee>
    </div>
</asp:Content>

------解决方案--------------------
<div id="container:">这里多个冒号啥意思？
------解决方案--------------------
css代码也要改下，改成这样：

 #container

        {

            width: 900px;

            height: 390px;

            background-color: Lavender;

            float: none;

            margin-top: 0px;

            margin-bottom: 0px;

            margin-left: auto;

            margin-right: auto;

            line-height: 390px;

            overflow: hidden;

        }