我想将模态对话框的位置设置得更低，我试图改变bootstrap.css文件的这么多属性，但没有一个更改有效，我必须更改的属性是什么类？ / p>
<!DOCTYPE html>
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta charset="utf-8">
<title>Bootstrap Login Form</title>
<meta name="generator" content="Bootply" />
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
<link href="css/bootstrap.min.css" rel="stylesheet">
<!--[if lt IE 9]>
<script src="//html5shim.googlecode.com/svn/trunk/html5.js"></script>
<![endif]-->
<link href="css/styles.css" rel="stylesheet">
</head>
<body>
<!--login modal-->
<div id="loginModal" class="modal show" tabindex="-1" role="dialog" aria-hidden="true">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
<h1 class="text-center">Login</h1>
</div>
<div class="modal-body">
<form class="form col-md-12 center-block">
<div class="form-group">
<input type="text" class="form-control input-lg" placeholder="Email">
</div>
<div class="form-group">
<input type="password" class="form-control input-lg" placeholder="Password">
</div>
<div class="form-group">
<button class="btn btn-primary btn-lg btn-block">Sign In</button>
<span class="pull-right"><a href="#">Register</a></span><span><a href="#">Need help?</a></span>
</div>
</form>
</div>
<div class="modal-footer">
<div class="col-md-12">
<button class="btn" data-dismiss="modal" aria-hidden="true">Cancel</button>
</div>
</div>
</div>
</div>
</div>
<!-- script references -->
<script src="//ajax.googleapis.com/ajax/libs/jquery/2.0.2/jquery.min.js"></script>
<script src="js/bootstrap.min.js"></script>
</body>
</html>