我的菜单列表不居中怎么回事？

<div class="index-menu">

<div class="menu-tips">The Menu</div>

<div class="public-container menu-list">

<ul class="clearfloat">

<li class="menu-item clearfloat">

<a class="title">

<h4>Voluptate cillum fugiat.</h4>

<p class="comment">Cheese, tomato, mushrooms, onions.</p>

</a>

<div class="line"></div>

<div class="price">$50</div>

</li>

</ul>

</div>

<div class="public-container menu-list">

<ul class="clearfloat">

<li class="menu-item clearfloat">

<a class="title">

<h4>Voluptate cillum fugiat.</h4>

<p class="comment">Cheese, tomato, mushrooms, onions.</p>

</a>

<div class="line"></div>

<div class="price">$50</div>

</li>

</ul>

</div>

<div class="public-container menu-list">

<ul class="clearfloat">

<li class="menu-item clearfloat">

<a class="title">

<h4>Voluptate cillum fugiat.</h4>

<p class="comment">Cheese, tomato, mushrooms, onions.</p>

</a>

<div class="line"></div>

<div class="price">$50</div>

</li>

</ul>

</div>

<div class="public-container menu-list">

<ul class="clearfloat">

<li class="menu-item clearfloat">

<a class="title">

<h4>Voluptate cillum fugiat.</h4>

<p class="comment">Cheese, tomato, mushrooms, onions.</p>

</a>

<div class="line"></div>

<div class="price">$50</div>

</li>

</ul>

</div>

<div class="public-container menu-list">

<ul class="clearfloat">

<li class="menu-item clearfloat">

<a class="title">

<h4>Voluptate cillum fugiat.</h4>

<p class="comment">Cheese, tomato, mushrooms, onions.</p>

</a>

<div class="line"></div>

<div class="price">$50</div>

</li>

</ul>

</div>

<div class="public-container menu-list">

<ul class="clearfloat">

<li class="menu-item clearfloat">

<a class="title">

<h4>Voluptate cillum fugiat.</h4>

<p class="comment">Cheese, tomato, mushrooms, onions.</p>

</a>

<div class="line"></div>

<div class="price">$50</div>

</li>

</ul>

</div>

<div class="public-container menu-list">

<ul class="clearfloat">

<li class="menu-item clearfloat">

<a class="title">

<h4>Voluptate cillum fugiat.</h4>

<p class="comment">Cheese, tomato, mushrooms, onions.</p>

</a>

<div class="line"></div>

<div class="price">$50</div>

</li>

</ul>

</div>

<div class="public-container menu-list">

<ul class="clearfloat">

<li class="menu-item clearfloat">

<a class="title">

<h4>Voluptate cillum fugiat.</h4>

<p class="comment">Cheese, tomato, mushrooms, onions.</p>

</a>

<div class="line"></div>

<div class="price">$50</div>

</li>

</ul>

</div>

</div>

.index-menu{

position: relative;

border-top: 4px solid #F34949;

}

.index-menu .menu-tips{

position: absolute;

left: 50%;

top: 0;

margin-left: -78px;

width: 156px;

height: 75px;

text-align: center;

line-height: 65px;

color: #FFF;

background-color: #F34949;

}

.index-menu .menu-tips:after{

position: absolute;

content: "";

left: 0;

bottom: 0;

width: 0;

height: 0;

border-left: 78px solid transparent;

border-right: 78px solid transparent;

border-bottom: 10px solid #FFF;

}

.index-menu .menu-list{

margin-top: 150px;

color: #555;

overflow: hidden;

}

.index-menu .menu-list ul{

width: 580px;

}

.index-menu .menu-item {

float: left;

width: 520px;

margin-right: 60px;

margin-bottom: 56px;

}

.index-menu .menu-item .title, .index-menu .menu-item .line{

float: left;

}

.index-menu .menu-item .price{

float: right;

}

.index-menu .menu-item .title{

width: 230px;

color: #555;

overflow: hidden;

white-space: nowrap;

text-overflow: ellipsis;

}

.index-menu .menu-item .comment{

margin-top: 4px;

color: #b7b7b7;

font-size: 12px;

}

.index-menu .menu-item .line{

margin-top:10px; 

width: 192px;

border-top: 1px solid #e3e1e1;

}