如何实现导航菜单居中对齐？尝试表格与text-align均无效

要让这个菜单水平居中，你之前的方法没用是因为菜单里的元素都加了float:left——浮动元素会脱离正常文档流，text-align:center对它们完全不起作用；表格布局又太冗余笨重。用Flexbox就能轻松解决，只需要修改两处CSS：

修改步骤 #

1. 让顶部栏容器居中内部元素 #

给.top-bar-2添加Flex布局属性，让它包裹的.navbar在水平方向居中：

.top-bar-2 {
  background-color: #2A0405;
  position: fixed;
  width: 100%;
  height: 50px;
  top: 90px;
  left: 0;
  z-index: 10;
  /* 新增代码 */
  display: flex;
  justify-content: center;
  align-items: center;
}

2. 调整导航栏内部布局 #

去掉.navbar的overflow:hidden，改用Flex布局让内部元素横向排列；同时删除.navbar a和.dropdown的float:left（浮动在这里已经没必要了）：

.navbar {
  /* 移除overflow:hidden */
  background-color: #2A0405;
  font-family: Gotham, "Helvetica Neue", Helvetica, Arial, "sans-serif";
  /* 新增代码 */
  display: flex;
}

.navbar a {
  /* 移除float:left */
  font-size: 16px;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

.dropdown {
  /* 移除float:left */
  overflow: hidden;
}

完整修改后代码 #

CSS #

body {
  background-color: #727288;
}

.top-bar-2 {
  background-color: #2A0405;
  position: fixed;
  width: 100%;
  height: 50px;
  top: 90px;
  left: 0;
  z-index: 10;
  display: flex;
  justify-content: center;
  align-items: center;
}

.navbar {
  background-color: #2A0405;
  font-family: Gotham, "Helvetica Neue", Helvetica, Arial, "sans-serif";
  display: flex;
}

.navbar a {
  font-size: 16px;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

.dropdown {
  overflow: hidden;
}

.dropdown .dropbtn {
  font-size: 16px;
  border: none;
  outline: none;
  color: white;
  padding: 14px 16px;
  background-color: inherit;
  font-family: inherit;
  margin: 0;
}

.navbar a:hover,
.dropdown:hover .dropbtn {
  background-color: red;
}

.dropdown-content {
  display: none;
  position: absolute;
  background-color: #f9f9f9;
  min-width: 160px;
  box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
  z-index: 1;
}

.dropdown-content a {
  float: none;
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
  text-align: left;
}

.dropdown-content a:hover {
  background-color: #ddd;
}

.dropdown:hover .dropdown-content {
  display: block;
}

HTML（无需修改） #

<div class="top-bar-2">
  <div class="navbar">
    <a href="#home">Home</a>
    <div class="dropdown">
      <button class="dropbtn">Sound</button>
      <div class="dropdown-content">
        <a href="#">Link 1</a>
        <a href="#">Link 2</a>
        <a href="#">Link 3</a>
      </div>
    </div>
    <div class="dropdown">
      <button class="dropbtn">Videos</button>
      <div class="dropdown-content">
        <a href="#">Link 1</a>
        <a href="#">Link 2</a>
        <a href="#">Link 3</a>
      </div>
    </div>
    <div class="dropdown">
      <button class="dropbtn">Recipes</button>
      <div class="dropdown-content">
        <a href="#">Link 1</a>
        <a href="#">Link 2</a>
        <a href="#">Link 3</a>
      </div>
    </div>
  </div>
</div>

原理说明 #

Flexbox是现代CSS布局方案：

• .top-bar-2通过justify-content:center让子元素（.navbar）在水平方向居中
• .navbar用display:flex让内部的链接和下拉容器横向整齐排列，同时去掉浮动属性，避免脱离文档流导致的布局问题

内容的提问来源于stack exchange，提问作者timbukto