如何使用CSS使菜单居中

Question

我正在尝试制作全宽度菜单，其中菜单项居中，但由于某种原因，我对对齐的所有操作似乎都没有效果。

我可能会遗漏某些东西或发生冲突吗？

我非常感谢任何和所有的帮助。

#menu-bar {
  left: -2px;
  width: 100%;
  margin: 0px 0px 0px 0px;
  padding: 6px 6px 4px 6px;
  /*height: 40px;*/
  line-height: 100%;
  border-radius: 0px;
  -webkit-border-radius: 0px;
  -moz-border-radius: 0px;
  box-shadow: 2px 2px 3px #666666;
  -webkit-box-shadow: 2px 2px 3px #666666;
  -moz-box-shadow: 2px 2px 3px #666666;
  background: #C2C2C2;
  border: double 1px #6D6D6D;
  position: relative;
  z-index: 999;
  top: -9px;
  left: -9px;
  width: 105%;
}
#menu-bar li {
  margin: 0px 0px 0px 0px;
  padding: 0px 6px 0px 6px;
  float: left;
  position: relative;
  list-style: none;
}
#menu-bar a {
  font-weight: bold;
  font-family: 'arial black';
  font-style: normal;
  font-size: 12px;
  color: #0A0A0A;
  text-decoration: none;
  display: block;
  padding: 7px 20px 6px 20px;
  margin: 0;
  margin-bottom: 0px;
  border-radius: 0px;
  -webkit-border-radius: 0px;
  -moz-border-radius: 0px;
  text-shadow: 0px 0px 3px #FFFFFF;
}
#menu-bar li ul li a {
  margin: 0;
}
#menu-bar .active a,
#menu-bar li:hover > a {
  background: #C2C2C2;
  color: #000000;
  -webkit-box-shadow: 0 1px 1px rgba(0, 0, 0, .2);
  -moz-box-shadow: 0 1px 1px rgba(0, 0, 0, .2);
  box-shadow: 0 1px 1px rgba(0, 0, 0, .2);
  text-shadow: 0px 0px 3px #FFFFFF;
}
#menu-bar ul li:hover a,
#menu-bar li:hover li a {
  background: none;
  border: none;
  color: #666;
  -box-shadow: none;
  -webkit-box-shadow: none;
  -moz-box-shadow: none;
}
#menu-bar ul a:hover {
  background: #FFFFFF !important;
  color: #000000 !important;
  border-radius: 0;
  -webkit-border-radius: 0;
  -moz-border-radius: 0;
  text-shadow: 2px 2px 3px #FFFFFF;
}
#menu-bar li:hover > ul {
  display: block;
}
#menu-bar ul {
  background: #DDDDDD;
  background: linear-gradient(top, #FFFFFF, #CFCFCF);
  background: -ms-linear-gradient(top, #FFFFFF, #CFCFCF);
  background: -webkit-gradient(linear, left top, left bottom, from(#FFFFFF), to(#CFCFCF));
  background: -moz-linear-gradient(top, #FFFFFF, #CFCFCF);
  display: none;
  margin: 0;
  padding: 0;
  width: 185px;
  position: absolute;
  /*top: 31px;*/
  left: 0;
  border: solid 1px #B4B4B4;
  border-radius: 10px;
  -webkit-border-radius: 10px;
  -moz-border-radius: 10px;
  -webkit-box-shadow: 2px 2px 3px #222222;
  -moz-box-shadow: 2px 2px 3px #222222;
  box-shadow: 2px 2px 3px #222222;
}
#menu-bar ul li {
  float: none;
  margin: 0;
  padding: 0;
}
#menu-bar ul a {
  padding: 10px 0px 10px 15px;
  color: #424242 !important;
  font-size: 12px;
  font-style: normal;
  font-family: arial;
  font-weight: normal;
  text-shadow: 2px 2px 3px #FFFFFF;
}
#menu-bar ul li:first-child > a {
  border-top-left-radius: 10px;
  -webkit-border-top-left-radius: 10px;
  -moz-border-radius-topleft: 10px;
  border-top-right-radius: 10px;
  -webkit-border-top-right-radius: 10px;
  -moz-border-radius-topright: 10px;
}
#menu-bar ul li:last-child > a {
  border-bottom-left-radius: 10px;
  -webkit-border-bottom-left-radius: 10px;
  -moz-border-radius-bottomleft: 10px;
  border-bottom-right-radius: 10px;
  -webkit-border-bottom-right-radius: 10px;
  -moz-border-radius-bottomright: 10px;
}
#menu-bar:after {
  content: ".";
  display: block;
  clear: both;
  visibility: hidden;
  line-height: 0;
  height: 0;
}
#menu-bar {
  display: inline-block;
}
html[xmlns] #menu-bar {
  display: block;
}
* html #menu-bar {
  height: 1%;
}

<ul id="menu-bar">
  <li class="active"><a href="#">Home</a>
  </li>
  <li><a href="#">Products</a>
    <ul>
      <li><a href="#">Products Sub Menu 1</a>
      </li>
      <li><a href="#">Products Sub Menu 2</a>
      </li>
      <li><a href="#">Products Sub Menu 3</a>
      </li>
      <li><a href="#">Products Sub Menu 4</a>
      </li>
    </ul>
  </li>
  <li><a href="#">Services</a>
    <ul>
      <li><a href="#">Services Sub Menu 1</a>
      </li>
      <li><a href="#">Services Sub Menu 2</a>
      </li>
      <li><a href="#">Services Sub Menu 3</a>
      </li>
      <li><a href="#">Services Sub Menu 4</a>
      </li>
    </ul>
  </li>
  <li><a href="#">About</a>
  </li>
  <li><a href="#">Contact Us</a>
  </li>
</ul>

Answer 1

#menu-bar { text-align:center; }
#menu-bar ul { text-align: left; }
#menu-bar > li { float:none; display:inline-block; }