JSFiddle - React, Tailwind, and code Playground

HTML

<div class="column sidebar" id="right_menu">
        <div class="section">
            <ul class="links yan-menu"><li class="menu-411 first"><a title="" href="/2012-mali-takvimi" style="background-color: rgb(230, 234, 240);">MALİ / VERGİ TAKVİMİ</a></li>
<li class="menu-413"><a href="/sirkuler" style="background-color: rgb(222, 227, 235);">SİRKÜLERLER</a></li>
<li class="menu-349"><a href="/node/7" style="background-color: rgb(222, 227, 235);">LİNKLER</a></li>
<li class="menu-418 last"><a href="/faydali_bilgiler" style="background-color: rgb(209, 217, 228);">FAYDALI BİLGİLER</a></li>
</ul>        </div>
          </div>

CSS

#right_menu {
    list-style-type: none;
    position: relative;
    z-index: 5;
    float: left;
    margin-top:60px;
}

#right_menu a {
  color: #002C6A;
  display: block;
  font-family: 'DINPro-Bold';
  font-size: 15px;
  padding: 15px 0 15px 80px;
  width: 220px;
}

#right_menu a:hover {
    color: #FFF;
    font-size: 15px;
    font-family: 'DINPro-Bold';
}

#right_menu ul li {
    list-style-type: none;
    border-bottom:1px solid #e5e5e5;
    margin: 0 0 0 0;
}

ul, ol, .item-list ul {
  margin-bottom: 1.5em;
  padding-left: 0px;
}

JavaScript

$(document).ready(function(){
    var bg;
    $("#right_menu a").mouseover(function() {
        bg = $(this).css('background-color');
         $(this).animate({ backgroundColor:'#002C6A'},500);
    }).mouseout(function() {
        $(this).animate({ backgroundColor:bg},500);
    });       
});