无法将 CSS 的块元素居中

Question

最近我的一个朋友给我发了一个相当不错的菜单代码，可以在我的网站上使用。但是该菜单的 CSS 使其左对齐。我仍然希望它与 width: 100%; 一起使用，但 项目和子项目与中心对齐 。我尝试删除所有 float: left;，将 text-align 更改为 center，甚至添加 margin: 0px auto;，但这些都不起作用。这是菜单的代码（注意：因为菜单是响应式的，所以媒体查询会导致 ul 在运行模式下的片段不在 "Full Page" 模式下时从视图中隐藏：

(function($) {

  $.fn.menumaker = function(options) {

    var cssmenu = $(this),
      settings = $.extend({
        title: "Menu",
        format: "dropdown",
        sticky: false
      }, options);

    return this.each(function() {
      cssmenu.prepend('<div id="menu-button">' + settings.title + '</div>');
      $(this).find("#menu-button").on('click', function() {
        $(this).toggleClass('menu-opened');
        var mainmenu = $(this).next('ul');
        if (mainmenu.hasClass('open')) {
          mainmenu.hide().removeClass('open');
        } else {
          mainmenu.show().addClass('open');
          if (settings.format === "dropdown") {
            mainmenu.find('ul').show();
          }
        }
      });

      cssmenu.find('li ul').parent().addClass('has-sub');

      multiTg = function() {
        cssmenu.find(".has-sub").prepend('<span class="submenu-button"></span>');
        cssmenu.find('.submenu-button').on('click', function() {
          $(this).toggleClass('submenu-opened');
          if ($(this).siblings('ul').hasClass('open')) {
            $(this).siblings('ul').removeClass('open').hide();
          } else {
            $(this).siblings('ul').addClass('open').show();
          }
        });
      };

      if (settings.format === 'multitoggle') multiTg();
      else cssmenu.addClass('dropdown');

      if (settings.sticky === true) cssmenu.css('position', 'fixed');

      resizeFix = function() {
        if ($(window).width() > 768) {
          cssmenu.find('ul').show();
        }

        if ($(window).width() <= 768) {
          cssmenu.find('ul').hide().removeClass('open');
        }
      };
      resizeFix();
      return $(window).on('resize', resizeFix);

    });
  };
})(jQuery);

(function($) {
  $(document).ready(function() {

    $(document).ready(function() {
      $("#cssmenu").menumaker({
        title: "Menu",
        format: "multitoggle"
      });

      $("#cssmenu").prepend("<div id='menu-line'></div>");

      var foundActive = false,
        activeElement, linePosition = 0,
        menuLine = $("#cssmenu #menu-line"),
        lineWidth, defaultPosition, defaultWidth;

      $("#cssmenu > ul > li").each(function() {
        if ($(this).hasClass('active')) {
          activeElement = $(this);
          foundActive = true;
        }
      });

      if (foundActive === false) {
        activeElement = $("#cssmenu > ul > li").first();
      }

      defaultWidth = lineWidth = activeElement.width();

      defaultPosition = linePosition = activeElement.position().left;

      menuLine.css("width", lineWidth);
      menuLine.css("left", linePosition);

      $("#cssmenu > ul > li").hover(function() {
          activeElement = $(this);
          lineWidth = activeElement.width();
          linePosition = activeElement.position().left;
          menuLine.css("width", lineWidth);
          menuLine.css("left", linePosition);
        },
        function() {
          menuLine.css("left", defaultPosition);
          menuLine.css("width", defaultWidth);
        });

    });

  });
})(jQuery);

@import url(http://fonts.googleapis.com/css?family=Open+Sans);
 #cssmenu,
#cssmenu ul,
#cssmenu ul li,
#cssmenu ul li a,
#cssmenu #menu-button {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}
#cssmenu:after,
#cssmenu > ul:after {
  content: ".";
  display: block;
  clear: both;
  visibility: hidden;
  line-height: 0;
  height: 0;
}
#cssmenu #menu-button {
  display: none;
}
#cssmenu {
  width: auto;
  font-family: 'Open Sans', sans-serif;
  line-height: 1;
  background: #ffffff;
}
#menu-line {
  position: absolute;
  top: 0;
  left: 0;
  height: 3px;
  background: #009ae1;
  -webkit-transition: all 0.25s ease-out;
  -moz-transition: all 0.25s ease-out;
  -ms-transition: all 0.25s ease-out;
  -o-transition: all 0.25s ease-out;
  transition: all 0.25s ease-out;
}
#cssmenu > ul > li {
  float: left;
}
#cssmenu.align-center > ul {
  font-size: 0;
  text-align: center;
}
#cssmenu.align-center > ul > li {
  display: inline-block;
  float: none;
}
#cssmenu.align-center ul ul {
  text-align: left;
}
#cssmenu.align-right > ul > li {
  float: right;
}
#cssmenu.align-right ul ul {
  text-align: right;
}
#cssmenu > ul > li > a {
  padding: 20px;
  font-size: 12px;
  text-decoration: none;
  text-transform: uppercase;
  color: #000000;
  -webkit-transition: color .2s ease;
  -moz-transition: color .2s ease;
  -ms-transition: color .2s ease;
  -o-transition: color .2s ease;
  transition: color .2s ease;
}
#cssmenu > ul > li:hover > a,
#cssmenu > ul > li.active > a {
  color: #009ae1;
}
#cssmenu > ul > li.has-sub > a {
  padding-right: 25px;
}
#cssmenu > ul > li.has-sub > a::after {
  position: absolute;
  top: 21px;
  right: 10px;
  width: 4px;
  height: 4px;
  border-bottom: 1px solid #000000;
  border-right: 1px solid #000000;
  content: "";
  -webkit-transform: rotate(45deg);
  -moz-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  transform: rotate(45deg);
  -webkit-transition: border-color 0.2s ease;
  -moz-transition: border-color 0.2s ease;
  -ms-transition: border-color 0.2s ease;
  -o-transition: border-color 0.2s ease;
  transition: border-color 0.2s ease;
}
#cssmenu > ul > li.has-sub:hover > a::after {
  border-color: #009ae1;
}
#cssmenu ul ul {
  position: absolute;
  left: -9999px;
}
#cssmenu li:hover > ul {
  left: auto;
}
#cssmenu.align-right li:hover > ul {
  right: 0;
}
#cssmenu ul ul ul {
  margin-left: 100%;
  top: 0;
}
#cssmenu.align-right ul ul ul {
  margin-left: 0;
  margin-right: 100%;
}
#cssmenu ul ul li {
  height: 0;
  -webkit-transition: height .2s ease;
  -moz-transition: height .2s ease;
  -ms-transition: height .2s ease;
  -o-transition: height .2s ease;
  transition: height .2s ease;
}
#cssmenu ul li:hover > ul > li {
  height: 32px;
}
#cssmenu ul ul li a {
  padding: 10px 20px;
  width: 160px;
  font-size: 12px;
  background: #333333;
  text-decoration: none;
  color: #dddddd;
  -webkit-transition: color .2s ease;
  -moz-transition: color .2s ease;
  -ms-transition: color .2s ease;
  -o-transition: color .2s ease;
  transition: color .2s ease;
}
#cssmenu ul ul li:hover > a,
#cssmenu ul ul li a:hover {
  color: #ffffff;
}
#cssmenu ul ul li.has-sub > a::after {
  position: absolute;
  top: 13px;
  right: 10px;
  width: 4px;
  height: 4px;
  border-bottom: 1px solid #dddddd;
  border-right: 1px solid #dddddd;
  content: "";
  -webkit-transform: rotate(-45deg);
  -moz-transform: rotate(-45deg);
  -ms-transform: rotate(-45deg);
  -o-transform: rotate(-45deg);
  transform: rotate(-45deg);
  -webkit-transition: border-color 0.2s ease;
  -moz-transition: border-color 0.2s ease;
  -ms-transition: border-color 0.2s ease;
  -o-transition: border-color 0.2s ease;
  transition: border-color 0.2s ease;
}
#cssmenu.align-right ul ul li.has-sub > a::after {
  right: auto;
  left: 10px;
  border-bottom: 0;
  border-right: 0;
  border-top: 1px solid #dddddd;
  border-left: 1px solid #dddddd;
}
#cssmenu ul ul li.has-sub:hover > a::after {
  border-color: #ffffff;
}
@media all and (max-width: 768px),
only screen and (-webkit-min-device-pixel-ratio: 2) and (max-width: 1024px),
only screen and (min--moz-device-pixel-ratio: 2) and (max-width: 1024px),
only screen and (-o-min-device-pixel-ratio: 2/1) and (max-width: 1024px),
only screen and (min-device-pixel-ratio: 2) and (max-width: 1024px),
only screen and (min-resolution: 192dpi) and (max-width: 1024px),
only screen and (min-resolution: 2dppx) and (max-width: 1024px) {
  #cssmenu {
    width: 100%;
  }
  #cssmenu ul {
    width: 100%;
    display: none;
  }
  #cssmenu.align-center > ul,
  #cssmenu.align-right ul ul {
    text-align: left;
  }
  #cssmenu ul li,
  #cssmenu ul ul li,
  #cssmenu ul li:hover > ul > li {
    width: 100%;
    height: auto;
    border-top: 1px solid rgba(120, 120, 120, 0.15);
  }
  #cssmenu ul li a,
  #cssmenu ul ul li a {
    width: 100%;
  }
  #cssmenu > ul > li,
  #cssmenu.align-center > ul > li,
  #cssmenu.align-right > ul > li {
    float: none;
    display: block;
  }
  #cssmenu ul ul li a {
    padding: 20px 20px 20px 30px;
    font-size: 12px;
    color: #000000;
    background: none;
  }
  #cssmenu ul ul li:hover > a,
  #cssmenu ul ul li a:hover {
    color: #000000;
  }
  #cssmenu ul ul ul li a {
    padding-left: 40px;
  }
  #cssmenu ul ul,
  #cssmenu ul ul ul {
    position: relative;
    left: 0;
    right: auto;
    width: 100%;
    margin: 0;
  }
  #cssmenu > ul > li.has-sub > a::after,
  #cssmenu ul ul li.has-sub > a::after {
    display: none;
  }
  #menu-line {
    display: none;
  }
  #cssmenu #menu-button {
    display: block;
    padding: 20px;
    color: #000000;
    cursor: pointer;
    font-size: 12px;
    text-transform: uppercase;
  }
  #cssmenu #menu-button::after {
    content: '';
    position: absolute;
    top: 20px;
    right: 20px;
    display: block;
    width: 15px;
    height: 2px;
    background: #000000;
  }
  #cssmenu #menu-button::before {
    content: '';
    position: absolute;
    top: 25px;
    right: 20px;
    display: block;
    width: 15px;
    height: 3px;
    border-top: 2px solid #000000;
    border-bottom: 2px solid #000000;
  }
  #cssmenu .submenu-button {
    position: absolute;
    z-index: 10;
    right: 0;
    top: 0;
    display: block;
    border-left: 1px solid rgba(120, 120, 120, 0.15);
    height: 52px;
    width: 52px;
    cursor: pointer;
  }
  #cssmenu .submenu-button::after {
    content: '';
    position: absolute;
    top: 21px;
    left: 26px;
    display: block;
    width: 1px;
    height: 11px;
    background: #000000;
    z-index: 99;
  }
  #cssmenu .submenu-button::before {
    content: '';
    position: absolute;
    left: 21px;
    top: 26px;
    display: block;
    width: 11px;
    height: 1px;
    background: #000000;
    z-index: 99;
  }
  #cssmenu .submenu-button.submenu-opened:after {
    display: none;
  }
}

<div id='cssmenu'>
  <ul>
    <li><a href='#'>Home</a>
    </li>
    <li class='active has-sub'><a href='#'>Products</a>
      <ul>
        <li class='has-sub'><a href='#'>Product 1</a>
          <ul>
            <li><a href='#'>Sub Product</a>
            </li>
            <li><a href='#'>Sub Product</a>
            </li>
          </ul>
        </li>
        <li class='has-sub'><a href='#'>Product 2</a>
          <ul>
            <li><a href='#'>Sub Product</a>
            </li>
            <li><a href='#'>Sub Product</a>
            </li>
          </ul>
        </li>
      </ul>
    </li>
    <li><a href='#'>About</a>
    </li>
    <li><a href='#'>Contact</a>
    </li>
  </ul>
</div>

Answer 1

我想你有所有的工作部件......这似乎是有效的。

   #cssmenu.align-center > ul {
      font-size: 0;
      text-align: center;
    }
    #cssmenu.align-center > ul > li {
      display: inline-block;
      float: none;
    }

body {
  background: black;
}
@import url(http://fonts.googleapis.com/css?family=Open+Sans);
 #cssmenu,
#cssmenu ul,
#cssmenu ul li,
#cssmenu ul li a,
#cssmenu #menu-button {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}
#cssmenu:after,
#cssmenu > ul:after {
  content: ".";
  display: block;
  clear: both;
  visibility: hidden;
  line-height: 0;
  height: 0;
}
#cssmenu #menu-button {
  display: none;
}
#cssmenu {
  width: auto;
  font-family: 'Open Sans', sans-serif;
  line-height: 1;
  background: #ffffff;
}
#menu-line {
  position: absolute;
  top: 0;
  left: 0;
  height: 3px;
  background: #009ae1;
  -webkit-transition: all 0.25s ease-out;
  -moz-transition: all 0.25s ease-out;
  -ms-transition: all 0.25s ease-out;
  -o-transition: all 0.25s ease-out;
  transition: all 0.25s ease-out;
}
#cssmenu > ul > li {
  display: inline-block;
}
#cssmenu.align-center > ul {
  font-size: 0;
  text-align: center;
}
#cssmenu.align-center > ul > li {
  display: inline-block;
  float: none;
}
#cssmenu.align-center ul ul {
  text-align: left;
}
#cssmenu.align-right > ul > li {
  float: right;
}
#cssmenu.align-right ul ul {
  text-align: right;
}
#cssmenu > ul > li > a {
  padding: 20px;
  font-size: 12px;
  text-decoration: none;
  text-transform: uppercase;
  color: #000000;
  -webkit-transition: color .2s ease;
  -moz-transition: color .2s ease;
  -ms-transition: color .2s ease;
  -o-transition: color .2s ease;
  transition: color .2s ease;
}
#cssmenu > ul > li:hover > a,
#cssmenu > ul > li.active > a {
  color: #009ae1;
}
#cssmenu > ul > li.has-sub > a {
  padding-right: 25px;
}
#cssmenu > ul > li.has-sub > a::after {
  position: absolute;
  top: 21px;
  right: 10px;
  width: 4px;
  height: 4px;
  border-bottom: 1px solid #000000;
  border-right: 1px solid #000000;
  content: "";
  -webkit-transform: rotate(45deg);
  -moz-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  transform: rotate(45deg);
  -webkit-transition: border-color 0.2s ease;
  -moz-transition: border-color 0.2s ease;
  -ms-transition: border-color 0.2s ease;
  -o-transition: border-color 0.2s ease;
  transition: border-color 0.2s ease;
}
#cssmenu > ul > li.has-sub:hover > a::after {
  border-color: #009ae1;
}
#cssmenu ul ul {
  position: absolute;
  left: -9999px;
}
#cssmenu li:hover > ul {
  left: auto;
}
#cssmenu.align-right li:hover > ul {
  right: 0;
}
#cssmenu ul ul ul {
  margin-left: 100%;
  top: 0;
}
#cssmenu.align-right ul ul ul {
  margin-left: 0;
  margin-right: 100%;
}
#cssmenu ul ul li {
  height: 0;
  -webkit-transition: height .2s ease;
  -moz-transition: height .2s ease;
  -ms-transition: height .2s ease;
  -o-transition: height .2s ease;
  transition: height .2s ease;
}
#cssmenu ul li:hover > ul > li {
  height: 32px;
}
#cssmenu ul ul li a {
  padding: 10px 20px;
  width: 160px;
  font-size: 12px;
  background: #333333;
  text-decoration: none;
  color: #dddddd;
  -webkit-transition: color .2s ease;
  -moz-transition: color .2s ease;
  -ms-transition: color .2s ease;
  -o-transition: color .2s ease;
  transition: color .2s ease;
}
#cssmenu ul ul li:hover > a,
#cssmenu ul ul li a:hover {
  color: #ffffff;
}
#cssmenu ul ul li.has-sub > a::after {
  position: absolute;
  top: 13px;
  right: 10px;
  width: 4px;
  height: 4px;
  border-bottom: 1px solid #dddddd;
  border-right: 1px solid #dddddd;
  content: "";
  -webkit-transform: rotate(-45deg);
  -moz-transform: rotate(-45deg);
  -ms-transform: rotate(-45deg);
  -o-transform: rotate(-45deg);
  transform: rotate(-45deg);
  -webkit-transition: border-color 0.2s ease;
  -moz-transition: border-color 0.2s ease;
  -ms-transition: border-color 0.2s ease;
  -o-transition: border-color 0.2s ease;
  transition: border-color 0.2s ease;
}
#cssmenu.align-right ul ul li.has-sub > a::after {
  right: auto;
  left: 10px;
  border-bottom: 0;
  border-right: 0;
  border-top: 1px solid #dddddd;
  border-left: 1px solid #dddddd;
}
#cssmenu ul ul li.has-sub:hover > a::after {
  border-color: #ffffff;
}

<div id='cssmenu' class="align-center">
  <ul>
    <li><a href='#'>Home</a>
    </li>
    <li class='active has-sub'><a href='#'>Products</a>
      <ul>
        <li class='has-sub'><a href='#'>Product 1</a>
          <ul>
            <li><a href='#'>Sub Product</a>
            </li>
            <li><a href='#'>Sub Product</a>
            </li>
          </ul>
        </li>
        <li class='has-sub'><a href='#'>Product 2</a>
          <ul>
            <li><a href='#'>Sub Product</a>
            </li>
            <li><a href='#'>Sub Product</a>
            </li>
          </ul>
        </li>
      </ul>
    </li>
    <li><a href='#'>About</a>
    </li>
    <li><a href='#'>Contact</a>
    </li>
  </ul>
</div>

Answer 2

您是否尝试将 "auto" 更改为“100%”？它在#cssmenu "width:auto" 上。当我将其更改为“100%”时，它以预览为中心。

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