标题隐藏在下拉菜单后面答案

【问题标题】：Heading hides behind dropdown menu标题隐藏在下拉菜单后面
【发布时间】：2016-11-27 17:25:57
【问题描述】：

我正在尝试创建一个网页手已经写了以下代码：

body {
  font-size: 16px;
  color: #fff;
  background-color: #4203A1;
  font-family: 'Roboto', sans-serif;
}

#header-nav {
  background-color: #8605E9;
  border-radius: 0;
  border: 3px solid black;
}

.navbar-brand h1 {
  font-size: 1.5em;
  margin-top: -8px;
  margin-bottom: 2px;
  font-weight: bold;
  text-transform: uppercase;
  line-height: 1.5;
  text-align: left;
}

.navbar-default .navbar-brand {
  color: #fff;
}

.dropdown-menu {
  width: 100%;
  text-align: center;
  margin-top: 53px;
  border: 1px solid black
}

.dropdown button {
  background-color: #fff;
}

.navbar-header button.navbar-toggle {
  clear: both;
  margin-top: -42px;
}

.heading {
  /*position: relative;*/
}

#menu-sections section {
  border: 3px solid black;
  margin: 20px;
  background-color: #607353;
}

.col-xs-12 p {
  padding: 10px;
  text-align: left;
}

.col-xs-12 h3 {
  color: #000000;
}

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
<link href="https://fonts.googleapis.com/css?family=Roboto" rel="stylesheet">
<script src="https://code.jquery.com/jquery-1.11.3.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.js"></script>

<body>
  <header>
    <nav id="header-nav" class="navbar navbar-default">
      <div class="container">
        <div class="navbar-header">
          <div class="navbar-brand navbar-left">
            <h1> Food, LLC </h1>
          </div>
          <div class="dropdown">
            <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#collapsable-nav" aria-expanded="false">
              <span class="sr-only">Toggle navigation</span>
              <span class="icon-bar"></span>
              <span class="icon-bar"></span>
              <span class="icon-bar"></span>
            </button>
            <ul class="dropdown-menu hidden-sm hidden-lg hidden-md" role="menu" aria-labelledby="menu1" id="collapsable-nav">
              <li role="presentation"><a role="menuitem" tabindex="-1" href="#">Chicken</a></li>
              <li role="presentation"><a role="menuitem" tabindex="-1" href="#">Beef</a></li>
              <li role="presentation"><a role="menuitem" tabindex="-1" href="#">Sushi</a></li>
            </ul>
          </div>
        </div>
      </div>
      </div>
    </nav>
  </header>
<div id="heading" class="container text-center">
  <h2> Our Menu </h2>
</div>
<div id ="menu-sections" class="container">
  <div class="col-xs-12 text-center">
    <section><h3> Chicken </h3>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting   industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p></section></div>
  <div class="col-xs-12 text-center">
    <section><h3> Beef </h3>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p></section>
  </div>
  <div class="col-xs-12 text-center">
    <section><h3> Sushi </h3>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p></section>
  </div>
  </body>

我正在使用 Bootstrap 框架，并在页面中创建了一个菜单按钮，当浏览器宽度减小时该按钮可见。问题是当我按下该按钮时，会出现一个下拉菜单，并且标题（我们的菜单）隐藏在它后面。我想要做的是标题（我们的菜单）和它下面的内容应该在我打开下拉菜单时向下移动，并在我关闭下拉菜单时向上移动到原始位置。我该如何做到这一点？另外，如何更改菜单的背景颜色？我试过了，但没有用：

.navbar-nav > li > .dropdown-menu {
  background-color: #e7e7e7;
}

【问题讨论】：

标签： html css twitter-bootstrap twitter-bootstrap-3

【解决方案1】：

你只需要将类.dropdown-menu的位置从absolute改为relative

.dropdown-menu {
    position: relative;
}

如果您不希望导航栏在显示下拉菜单时垂直扩展，那么您应该将margin-top: 0px; 添加到同一类

.dropdown-menu {
    position: relative;
    margin-top: 0px;
}

【讨论】：