老师，您好，请问按钮样式怎么加载不出来呢？我写的有问题？

按钮css：

#button{
   float:right;
}
#button button{
   width:80px;
   height:30px;
   color:white;
   background-color:#428BCA;
   border:1px solid #428BCA;
   border-left:2px solid white;
   border-top:2px solid white;
   border-radius:5px;
   font-weight:bold;
   cursor:pointer;
   box-shadow:5px 5px 12px #ccc;
}

jsp代码：

<section class="main">
    <div class="container">
        <c:forEach items="${messages}" var="msg">
            <div class="alt-item">
                <div class="alt-head">
                    <div class="alt-info">
                        <span>作者：<a href="">${msg.username}</a></span>
                        <span>时间：<fmt:formatDate pattern="yyyy-MM-dd HH:mm:ss" value="${msg.createTime}"/></span>
                    </div>
                </div>
                <div class="alt-content">
                    <h3>${msg.title}</h3>
                    <p>${msg.content}</p>
                </div>
                <div id="button">
                    <a href="">
                        <button>修改</button>
                    </a>
                    <a href="">
                        <button>删除</button>
                    </a>
                </div>
            </div>
        </c:forEach>
    </div>
</section>

我只是在老师给的代码基础上，在jsp中这么做了，css文件最后添加了，怎么加载不出效果呢？