3D菜单旋转，文字消失

Question

我是初学者，所以我需要一些帮助。我有这个菜单，当我在HOME按钮上使用鼠标时，主页按钮会旋转但不显示任何内容。当它旋转时，HOME文本消失。

(function($) {

  $.fn.menumaker = function(options) {

    var cssmenu = $(this), settings = $.extend({
      title: "Menu",
      format: "dropdown",
      breakpoint: 768,
      sticky: false
    }, options);

    return this.each(function() {
      cssmenu.find('li ul').parent().addClass('has-sub');
      if (settings.format != 'select') {
        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();
            }
          }
        });

        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');
      }

      else if (settings.format === 'select')
      {
        cssmenu.append('<select style="width: 100%"/>').addClass('select-list');
        var selectList = cssmenu.find('select');
        selectList.append('<option>' + settings.title + '</option>', {
          "selected": "selected",
          "value": ""});
        cssmenu.find('a').each(function() {
          var element = $(this), indentation = "";
          for (i = 1; i < element.parents('ul').length; i++)
          {
            indentation += '-';
          }
          selectList.append('<option value="' + $(this).attr('href') + '">' + indentation + element.text() + '</option');
        });
        selectList.on('change', function() {
          window.location = $(this).find("option:selected").val();
        });
      }

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

      resizeFix = function() {
        if ($(window).width() > settings.breakpoint) {
          cssmenu.find('ul').show();
          cssmenu.removeClass('small-screen');
          if (settings.format === 'select') {
            cssmenu.find('select').hide();
          }
          else {
            cssmenu.find("#menu-button").removeClass("menu-opened");
          }
        }

        if ($(window).width() <= settings.breakpoint && !cssmenu.hasClass("small-screen")) {
          cssmenu.find('ul').hide().removeClass('open');
          cssmenu.addClass('small-screen');
          if (settings.format === 'select') {
            cssmenu.find('select').show();
          }
        }
      };
      resizeFix();
      return $(window).on('resize', resizeFix);

    });
  };
})(jQuery);

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

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

      $("#cssmenu a").each(function() {
        var linkTitle = $(this).text();
        $(this).attr('data-title', linkTitle);
      });
    });

  });
})(jQuery);

@import url(http://fonts.googleapis.com/css?family=Raleway);
#cssmenu,
#cssmenu ul,
#cssmenu ul li,
#cssmenu ul li a,
#cssmenu #menu-button {
  margin: 0 auto;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: center;
  -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: Raleway, sans-serif;
  line-height: 1;
}
#cssmenu > ul {
  background: #3db2e1;
}
#cssmenu > ul > li {
  float: left;
  left: -50%;
  -webkit-perspective: 1000px;
  -moz-perspective: 1000px;
  perspective: 1000px;
}
#cssmenu.align-center > ul {
  font-size: 0;
  text-align: center;
}
#cssmenu.align-center > ul > li {
  display: inline-block;
  float: none;
}
#cssmenu.align-right > ul > li {
  float: right;
}
#cssmenu > ul > li > a {
  padding: 16px 20px;
  font-size: 14px;
  color: #ffffff;
  letter-spacing: 1px;
  text-transform: uppercase;
  text-decoration: none;
  background: #3db2e1;
  -webkit-transition: all .3s;
  -moz-transition: all .3s;
  -o-transition: all .3s;
  transition: all .3s;
  -webkit-transform-origin: 50% 0;
  -moz-transform-origin: 50% 0;
  transform-origin: 50% 0;
  -webkit-transform-style: preserve-3d;
  -moz-transform-style: preserve-3d;
  transform-style: preserve-3d;
}
#cssmenu > ul > li.active > a {
  color: #dff2fa;
}
#cssmenu > ul > li:hover > a,
#cssmenu > ul > li > a:hover {
  color: #dff2fa;
  -webkit-transform: rotateX(90deg) translateY(-23px);
  -moz-transform: rotateX(90deg) translateY(-23px);
  transform: rotateX(90deg) translateY(-23px);
  -ms-transform: none;
}
#cssmenu > ul > li > a::before {
  position: absolute;
  top: 100%;
  left: 0;
  z-index: -1;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  width: 100%;
  height: 100%;
  padding: 16px 20px;
  color: #dff2fa;
  background: #19799f;
  content: attr(data-title);
  -webkit-transition: background 0.3s;
  -moz-transition: background 0.3s;
  transition: background 0.3s;
  -webkit-transform: rotateX(-90deg);
  -moz-transform: rotateX(-90deg);
  transform: rotateX(-90deg);
  -webkit-transform-origin: 50% 0;
  -moz-transform-origin: 50% 0;
  transform-origin: 50% 0;
  -ms-transform: translateY(- -18px);
    }
#cssmenu > ul > li:hover > a::before,
#cssmenu > ul > li > a:hover::before {
  background: #3db2e1;
}
#cssmenu.small-screen {
  width: 100%;
}
#cssmenu.small-screen > ul,
#cssmenu.small-screen.align-center > ul {
  width: 100%;
  text-align: left;
}
#cssmenu.small-screen > ul > li,
#cssmenu.small-screen.align-center {
  float: none;
  display: block;
  border-top: 1px solid rgba(100, 100, 100, 0.1);
}
#cssmenu.small-screen > ul > li:hover > a,
#cssmenu.small-screen > ul > li > a:hover {
  color: #dff2fa;
  -webkit-transform: none;
  -moz-transform: none;
  transform: none;
  -ms-transform: none;
}
#cssmenu.small-screen > ul > li > a::before {
  display: none;
}
#cssmenu.small-screen #menu-button {
  display: block;
  padding: 16px 20px;
  cursor: pointer;
  font-size: 14px;
  text-decoration: none;
  color: #ffffff;
  text-transform: uppercase;
  letter-spacing: 1px;
  background: #3db2e1;
}
#cssmenu.small-screen #menu-button:after {
  content: "";
  position: absolute;
  right: 20px;
  top: 17px;
  display: block;
  -webkit-box-sizing: content-box;
  -moz-box-sizing: content-box;
  box-sizing: content-box;
  border-top: 2px solid #ffffff;
  border-bottom: 2px solid #ffffff;
  width: 22px;
  height: 3px;
}
#cssmenu.small-screen #menu-button.menu-opened:after {
  border-top: 2px solid #dff2fa;
  border-bottom: 2px solid #dff2fa;
}
#cssmenu.small-screen #menu-button:before {
  content: "";
  position: absolute;
  right: 20px;
  top: 27px;
  display: block;
  width: 22px;
  height: 2px;
  background: #ffffff;
}
#cssmenu.small-screen #menu-button.menu-opened:before {
  background: #dff2fa;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<div id='cssmenu' class='align-center'>
  <ul>
    <li class='active'><a href='index.html'>Home</a></li>
    <li><a href='customers.html'>Customers</a></li>
    <li><a href='about.html'>About</a></li>
    <li><a href='#'>Contact</a></li>
  </ul>
</div>