Question

我是 html 和 css 的新手，但我正在制作一个响应式下拉菜单，我无法找到为什么我的菜单/导航栏不会居中桌面版。

我从here找到了菜单并下载了它。

这是我的代码：

<style>
@import url(http://fonts.googleapis.com/css?family=roboto);

body {
  background: #212121;
  font-size: 22px;
  line-height: 32px;
  color: #ffffff;
  margin: 0;
  padding: 0;
  word-wrap: break-word !important;
  font-family: 'roboto', sans-serif;
}

h1 {
  font-size: 60px;
  text-align: center;
  color: #FFF;
}

h3 {
  font-size: 30px;
  line-height: 34px;
  text-align: center;
  color: #FFF;
}

h3 a { color: #FFF; }

a { color: #FFF; }

h1 {
  margin-top: 100px;
  text-align: center;
  font-size: 60px;
  line-height: 70px;
  font-family: 'roboto', sans-serif;
}

#container {
  margin: 0 auto;
  max-width: 890px;
}

p { text-align: center; }
 .toggle, [id^=drop] {
 display: none;
}

nav {
  margin: 0;
  padding: 0;
  background-color: #254441;
}

#logo {
  display: block;
  padding: 0 30px;
  float: left;
  font-size: 20px;
  line-height: 60px;
}

nav:after {
  content: "";
  display: table;
  clear: both;
}

nav ul {
  float: right;
  padding: 0;
  margin: 0;
  list-style: none;
  position: relative;
}

nav ul li {
  margin: 0px;
  display: inline-block;
  float: left;
  background-color: #254441;
}

nav a {
  display: block;
  padding: 0 20px;
  color: #FFF;
  font-size: 20px;
  line-height: 60px;
  text-decoration: none;
}

nav ul li ul li:hover { background: #000000; }

nav a:hover { background-color: #000000; }

nav ul ul {
  display: none;
  position: absolute;
  top: 60px;
}

nav ul li:hover > ul { display: inherit; }

nav ul ul li {
  width: 170px;
  float: none;
  display: list-item;
  position: relative;
}

nav ul ul ul li {
  position: relative;
  top: -60px;
  left: 170px;
}

li > a:after { content: ' +'; }

li > a:only-child:after { content: ''; }


/* Media Queries
--------------------------------------------- */

@media all and (max-width : 768px) {

#logo {
  display: block;
  padding: 0;
  width: 100%;
  text-align: center;
  float: none;
}

nav { margin: 0; }

.toggle + a,
 .menu { display: none; }

.toggle {
  display: block;
  background-color: #254441;
  padding: 0 20px;
  color: #FFF;
  font-size: 20px;
  line-height: 60px;
  text-decoration: none;
  border: none;
}

.toggle:hover { background-color: #000000; }

[id^=drop]:checked + ul { display: block; }

nav ul li {
  display: block;
  width: 100%;
}

nav ul ul .toggle,
 nav ul ul a { padding: 0 40px; }

nav ul ul ul a { padding: 0 80px; }

nav a:hover,
 nav ul ul ul a { background-color: #000000; }

nav ul li ul li .toggle,
 nav ul ul a { background-color: #212121; }

nav ul ul {
  float: none;
  position: static;
  color: #ffffff;
}

nav ul ul li:hover > ul,
nav ul li:hover > ul { display: none; }

nav ul ul li {
  display: block;
  width: 100%;
}

nav ul ul ul li { position: static;

}
}

@media all and (max-width : 330px) {

nav ul li {
  display: block;
  width: 94%;
}

}
</style>

<body>
<nav>

  <div id="logo">Demo Page</div>
  <label for="drop" class="toggle">Menu</label>
  <input type="checkbox" id="drop" />
  <ul class="menu">
    <li><a href="#">Home</a></li>
    <li> 
      <!-- First Tier Drop Down -->
      <label for="drop-1" class="toggle">Service +</label>
      <a href="#">Service</a>
      <input type="checkbox" id="drop-1"/>
      <ul>
        <li><a href="#">Service 1</a></li>
        <li><a href="#">Service 2</a></li>
        <li><a href="#">Service 3</a></li>
      </ul>
    </li>
    <li> 
      
      <!-- First Tier Drop Down -->
      <label for="drop-2" class="toggle">Portfolio +</label>
      <a href="#">Portfolio</a>
      <input type="checkbox" id="drop-2"/>
      <ul>
        <li><a href="#">Portfolio 1</a></li>
        <li><a href="#">Portfolio 2</a></li>
        <li> 
          
          <!-- Second Tier Drop Down -->
          <label for="drop-3" class="toggle">Works +</label>
          <a href="#">Works</a>
          <input type="checkbox" id="drop-3"/>
          <ul>
            <li><a href="#">HTML/CSS</a></li>
            <li><a href="#">jQuery</a></li>
            <li><a href="#">Python</a></li>
          </ul>
        </li>
      </ul>
    </li>
    <li><a href="#">Blog</a></li>
    <li><a href="#">Submit</a></li>
    <li><a href="#">Contact</a></li>
    <li><a href="#">About</a></li>
  </ul>
</nav>
<h1> Mobile-compatible Responsive Dropdown Menu Demo </h1>


</body>

Answer 1

试试这个。

#nav { width:750px; margin:0 auto; list-style:none; }

#nav li { float:left; }

#nav a { display:block; text-align:center; width:150px; /* fixed width */ text-decoration:none; }

方法＃1主要使用margin:auto;到center nav。如果您的菜单项（li / a）是固定宽度，则此方法可能是center nav center的最简单方法。用于nav Object的essentail代码段以粗体显示。

查看此site了解更多信息。希望它有所帮助！

为什么我不能将我的菜单栏/导航中心

1 个答案: