Горизонтальное меню в адаптивной верстке CSS

<header>
<nav id='kosecomege'>
<div class="presenceon"><a href="http://zornet.ru/">ZORNET.RU </a></div>
<div id="diences-dectivel"></div>
<div class="button"></div>
<ul>
<li class='active'><a href='#'>ГЛАВНАЯ</a></li>
<li><a href='#'>СКРИПТЫ</a></li>
<li><a href='#'>РАЗДЕЛЫ</a>
  <ul>
  <li><a href='#'>Под меню 1</a>

  </li>
  <li><a href='#'>Под меню 2</a>
  <ul>
  <li><a href='#'>Под разделы</a></li>
  <li><a href='#'>Под разделы</a></li>
  </ul>
  </li>
  </ul>
</li>
<li><a href='#'>CSS</a></li>
<li><a href='#'>VIDEO</a></li>
<li><a href='#'>CSS</a></li>
<li><a href='#'>СВЯЗЬ</a></li>
</ul>
</nav>
</header>

header {
  position: relative;
  width: 100%;
  background: #232121;
}

.presenceon {
  position: relative;
  z-index: 123;
  padding: 8px;
  font: 20px verdana;
  color: #0777db;
  float: left;
  width: 20%;
}

.presenceon a{
color:#dffda7;
}

nav{
position:relative;
width:975px;
margin:0 auto;
}

#kosecomege,#kosecomege ul,#kosecomege ul li,#kosecomege ul li a,#kosecomege #diences-dectivel{
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}

#kosecomege:after,#kosecomege > ul:after{
content:'.';
display:block;
clear:both;
visibility:hidden;
line-height:0;
height:0}

#kosecomege #diences-dectivel{
display:none}

#kosecomege {
  font-family: sans-serif;
  background: #232121;
}

#kosecomege > ul > li{
float:left}

#kosecomege > ul > li > a{
padding:17px;
font-size:12px;
letter-spacing:1px;
text-decoration:none;
color:#ddd;
font-weight:700;
}

#kosecomege > ul > li:hover > a,#kosecomege ul li.active a{
color:#fff}

#kosecomege > ul > li:hover,#kosecomege ul li.active:hover,#kosecomege ul li.active,#kosecomege ul li.has-sub.active:hover{
background:#2c7fbb!important;
-webkit-transition:background .5s ease;
-ms-transition:background .5s ease;
transition:background .5s ease;
}

#kosecomege > ul > li.has-sub > a{
padding-right:30px}

#kosecomege > ul > li.has-sub > a:after{
position:absolute;
top:22px;
right:11px;
width:8px;
height:2px;
display:block;
background:#ddd;
content:''}

#kosecomege > ul > li.has-sub > a:before{
position:absolute;
top:19px;
right:14px;
display:block;
width:2px;
height:8px;
background:#ddd;
content:'';
-webkit-transition:all .25s ease;
-ms-transition:all .25s ease;
transition:all .25s ease}

#kosecomege > ul > li.has-sub:hover > a:before{
top:23px;
height:0}

#kosecomege ul ul{
position:absolute;
left:-9999px}

#kosecomege ul ul li{
height:0;
-webkit-transition:all .25s ease;
-ms-transition:all .25s ease;
background:#333;
transition:all .25s ease}

#kosecomege ul ul li:hover{
}

#kosecomege li:hover > ul{
left:auto}

#kosecomege li:hover > ul > li{
height:35px}

#kosecomege ul ul ul{
margin-left:100%;
top:0}

#kosecomege ul ul li a{
border-bottom:1px solid rgba(150,150,150,0.15);
padding:11px 15px;
width:168px;
font-size:12px;
text-decoration:none;
color:#ddd;
font-weight:400;
}

#kosecomege ul ul li:last-child > a,#kosecomege ul ul li.last-item > a{
border-bottom:0}

#kosecomege ul ul li:hover > a,#kosecomege ul ul li a:hover{
color:#fff}

#kosecomege ul ul li.has-sub > a:after{
position:absolute;
top:16px;
right:11px;
width:8px;
height:2px;
display:block;
background:#ddd;
content:''}

#kosecomege ul ul li.has-sub > a:before{
position:absolute;
top:13px;
right:14px;
display:block;
width:2px;
height:8px;
background:#ddd;
content:'';
-webkit-transition:all .25s ease;
-ms-transition:all .25s ease;
transition:all .25s ease}

#kosecomege ul ul > li.has-sub:hover > a:before{
top:17px;
height:0}

#kosecomege ul ul li.has-sub:hover,#kosecomege ul li.has-sub ul li.has-sub ul li:hover{
background:#363636;
}

#kosecomege ul ul ul li.active a{
border-left:1px solid #333}

#kosecomege > ul > li.has-sub > ul > li.active > a,#kosecomege > ul ul > li.has-sub > ul > li.active> a{
border-top:1px solid #232121}

@media screen and (max-width:1000px){
.presenceon{
position:absolute;
top:0;
left: 0;
width:100%;
height:46px;
text-align:center;
padding:10px 0 0 0;
float:none}

.presenceon2{
display:none}

nav{
width:100%;
}

#kosecomege{
width:100%}

#kosecomege ul{
width:100%;
display:none}

#kosecomege ul li{
width:100%;
border-top:1px solid #444}

#kosecomege ul li:hover{
background:#363636;
}

#kosecomege ul ul li,#kosecomege li:hover > ul > li{
height:auto}

#kosecomege ul li a,#kosecomege ul ul li a{
width:100%;
border-bottom:0}

#kosecomege > ul > li{
float:none}

#kosecomege ul ul li a{
padding-left:25px}

#kosecomege ul ul li{
background:#232121!important;
}

#kosecomege ul ul li:hover{
background:#363636!important}

#kosecomege ul ul ul li a{
padding-left:35px}

#kosecomege ul ul li a{
color:#ddd;
background:none}

#kosecomege ul ul li:hover > a,#kosecomege ul ul li.active > a{
color:#fff}

#kosecomege ul ul,#kosecomege ul ul ul{
position:relative;
left:0;
width:100%;
margin:0;
text-align:left}

#kosecomege > ul > li.has-sub > a:after,#kosecomege > ul > li.has-sub > a:before,#kosecomege ul ul > li.has-sub > a:after,#kosecomege ul ul > li.has-sub > a:before{
display:none}

#kosecomege #diences-dectivel{
display:block;
padding:23px;
color:#ddd;
font-size:12px;
font-weight:700}

.button{
width:55px;
height:46px;
position:absolute;
right:0;
top:0;
cursor:pointer;
z-index: 12399994;
}

.button:after{
position:absolute;
top:22px;
right:20px;
display:block;
height:4px;
width:20px;
border-top:2px solid #dddddd;
border-bottom:2px solid #dddddd;
content:''}

.button:before{
-webkit-transition:all .3s ease;
-ms-transition:all .3s ease;
transition:all .3s ease;
position:absolute;
top:16px;
right:20px;
display:block;
height:2px;
width:20px;
background:#ddd;
content:''}

.button.menu-opened:after{
-webkit-transition:all .3s ease;
-ms-transition:all .3s ease;
transition:all .3s ease;
top:23px;
border:0;
height:2px;
width:19px;
background:#fff;
-webkit-transform:rotate(45deg);
-moz-transform:rotate(45deg);
-ms-transform:rotate(45deg);
-o-transform:rotate(45deg);
transform:rotate(45deg)}

.button.menu-opened:before{
top:23px;
background:#fff;
width:19px;
-webkit-transform:rotate(-45deg);
-moz-transform:rotate(-45deg);
-ms-transform:rotate(-45deg);
-o-transform:rotate(-45deg);
transform:rotate(-45deg)}

#kosecomege .submenu-button{
position:absolute;
z-index:99;
right:0;
top:0;
display:block;
border-left:1px solid #444;
height:46px;
width:46px;
cursor:pointer}

#kosecomege .submenu-button.submenu-opened{
background:#262626}

#kosecomege ul ul .submenu-button{
height:34px;
width:34px}

#kosecomege .submenu-button:after{
position:absolute;
top:22px;
right:19px;
width:8px;
height:2px;
display:block;
background:#ddd;
content:''}

#kosecomege ul ul .submenu-button:after{
top:15px;
right:13px}

#kosecomege .submenu-button.submenu-opened:after{
background:#fff}

#kosecomege .submenu-button:before{
position:absolute;
top:19px;
right:22px;
display:block;
width:2px;
height:8px;
background:#ddd;
content:''}

#kosecomege ul ul .submenu-button:before{
top:12px;
right:16px}

#kosecomege .submenu-button.submenu-opened:before{
display:none}

#kosecomege ul ul ul li.active a{
border-left:none}

#kosecomege > ul > li.has-sub > ul > li.active > a,#kosecomege > ul ul > li.has-sub > ul > li.active > a{
border-top:none}

}

(function($) {
$.fn.menumaker = function(options) {  
  var kosecomege = $(this), settings = $.extend({
  format: "dropdown",
  sticky: false
  }, options);
  return this.each(function() {
  $(this).find(".button").on('click', function(){
  $(this).toggleClass('menu-opened');
  var mainmenu = $(this).next('ul');
  if (mainmenu.hasClass('open')) {  
  mainmenu.slideToggle().removeClass('open');
  }
  else {
  mainmenu.slideToggle().addClass('open');
  if (settings.format === "dropdown") {
  mainmenu.find('ul').show();
  }
  }
  });
  kosecomege.find('li ul').parent().addClass('has-sub');
multiTg = function() {
  kosecomege.find(".has-sub").prepend('<span class="submenu-button"></span>');
  kosecomege.find('.submenu-button').on('click', function() {
  $(this).toggleClass('submenu-opened');
  if ($(this).siblings('ul').hasClass('open')) {
  $(this).siblings('ul').removeClass('open').slideToggle();
  }
  else {
  $(this).siblings('ul').addClass('open').slideToggle();
  }
  });
  };
  if (settings.format === 'multitoggle') multiTg();
  else kosecomege.addClass('dropdown');
  if (settings.sticky === true) kosecomege.css('position', 'fixed');
resizeFix = function() {
  var mediasize = 1000;
  if ($( window ).width() > mediasize) {
  kosecomege.find('ul').show();
  }
  if ($(window).width() <= mediasize) {
  kosecomege.find('ul').hide().removeClass('open');
  }
  };
  resizeFix();
  return $(window).on('resize', resizeFix);
  });
  };
})(jQuery);

(function($){
$(document).ready(function(){
$("#kosecomege").menumaker({
  format: "multitoggle"
});
});
})(jQuery);