想要使 div 居中

Question

嗨，我的问题是我实际上无法将我的 div 居中！ 它总是卡在左边。我已经尝试过 margin-left: auto;和margin-right: auto;，但它似乎不起作用。

这是 HTML：

    <ul class="menu">

        <li><a href="#" class="home">Acceuil</a></li>
        <li><a href="#" class="LoL">LoL</a>
            <ul>
                <li><a><span class="headlist">League of Legends</a></li>
                <li><a href="#">Funny games</a></li>
                <li><a href="#">Favorite builds</a></li>
                <li><a href="#">...</a></li>
            </ul>
        </li>
        <li><a href="#" class="ssf2">SSF2</a>
            <ul>
                <li><a><span class="headlist">Super Smash Flash 2</a>
                <li><a href="#">Intro</a></li>
                <li><a href="#">Events</a></li>
                <li><a href="#">Challenges</a></li>
            </ul>
        </li>
        <li><a href="#">RotMG</a></li>
        <li><a href="#">GMod</a></li>
        <li><a href="#" class="contact">Contact</a></li>
    </ul>

    <div>
        <p>
            HUEHUEHUEHUEHUEHUEHUE
        </p>
    </div>

这是css：

    html { 
background: url(bg.jpg) no-repeat center center fixed; 
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}

/* div */
div
{
text-align: center;
border-radius: 0 0 5px 5px;
width: 590px;
padding-left: 5px;
padding-right: 5px;
padding-top: 5px;
padding-bottom: 5px;
background-color: rgba(140,0,0,0.7);
margin-left: auto;
margin-right: auto;
text-shadow: 1px 1px 1px rgba(0,0,0,.5);
color: #f3f3f3;
font-family: Helvetica, Arial, sans-serif;
display: block;
position: absolute;
top: 38px;
left: 25%;
z-index: -50;
margin-left: auto;
margin-right: auto;
}

/* Reset de la liste (aucun style, etc.) */
.menu,
.menu ul,
.menu li,
.menu a,
.menu p 
{
margin: 0;
padding: 0;
border: none;
outline: none;
}

/* Menu */ 
.menu 
{
height: 40px;
width: 610px; /* Longueur du menu */

background: #760101;  /* couleur du gradient */
background: -moz-linear-gradient(#D20202, #760101); 
background: -webkit-gradient(linear,left bottom,left top,color-stop(0, #760101),color-stop(1, #D20202));    
background: -webkit-linear-gradient(#D20202, #760101);  
background: -o-linear-gradient(#D20202, #760101);
background: -ms-linear-gradient(#D20202, #760101);
background: linear-gradient(#D20202, #760101);

-webkit-border-radius: 5px;
-moz-border-radius: 5px;
border-radius: 13px;

display: block;
margin-left: auto;
margin-right: auto;
}

.menu li {
position: relative;
list-style: none;
float: left;
display: block;
height: 40px;
}

.menu li a {
display: block;
padding: 0 7px 0 40px;
margin: 6px 0;
line-height: 28px;
text-decoration: none;

border-left: 1px solid #4B0101;
border-right: 1px solid #5C0101;

font-family: Helvetica, Arial, sans-serif;
font-weight: bold;
font-size: 13px;

color: #f3f3f3;
text-shadow: 1px 1px 1px rgba(0,0,0,.6);

-webkit-transition: color .2s ease-in-out;
-moz-transition: color .2s ease-in-out;
-o-transition: color .2s ease-in-out;
-ms-transition: color .2s ease-in-out;
transition: color .2s ease-in-out;
}

.menu li:first-child a { border-left: none; }
.menu li:last-child a{ border-right: none; }

.menu li:hover > a { color: #FF9900; }

/* Sub-menu */

.menu ul {
position: absolute;
top: 40px;
left: 0;

opacity: 0;
background: #D20202;
background: -moz-linear-gradient(#760101, #D20202); 
background: -webkit-gradient(linear,left bottom,left top,color-stop(0, #D20202),color-stop(1, #760101));    
background: -webkit-linear-gradient(#760101, #D20202);  
background: -o-linear-gradient(#760101, #D20202);
background: -ms-linear-gradient(#760101, #D20202);
background: linear-gradient(#760101, #D20202);

-webkit-border-radius: 0 0 5px 5px;
-moz-border-radius: 0 0 5px 5px;
border-radius: 0 0 5px 5px;

-webkit-transition: opacity .25s ease .1s;
-moz-transition: opacity .25s ease .1s;
-o-transition: opacity .25s ease .1s;
-ms-transition: opacity .25s ease .1s;
transition: opacity .25s ease .1s;
}

.menu li:hover > ul { opacity: 1; }

.menu ul li {
height: 0;
overflow: hidden;
padding: 0;

-webkit-transition: height .25s ease .1s;
-moz-transition: height .25s ease .1s;
-o-transition: height .25s ease .1s;
-ms-transition: height .25s ease .1s;
transition: height .25s ease .1s;
}

.menu li:hover > ul li {
height: 36px;
overflow: visible;
padding: 0;
}

.menu ul li a {
width: 145px;
padding: 4px 0 4px 10px;
margin: 0;

border: none;
border-bottom: 1px solid #4B0101;
}

.menu ul li:last-child a { 
border: none; 
}

.LoL
{
background: url(LoLicon.png) no-repeat 6px center;
}

.home
{
background: url(home.png) no-repeat 6px center;
}

.ssf2
{
background: url(SSF2.png) no-repeat 6px center;
}

.contact
{
background: url(contact.png) no-repeat 6px center;
}

.headlist
{
color:#ff9900;
}

.menu ul li:first-child a { 
border-bottom: 3px solid #4B0101; 
}

我已经搜索了 2 个小时，所以请帮忙！ :O

Answer 1

Margin: 0 auto; 不适用于绝对定位。尝试从 div 中删除 position:absolute，然后它应该可以工作。

这里是fiddle

Answer 2

如果必须绝对定位（这意味着margin: auto 不起作用），那么您可以将CSS 更改为left: 50% 并添加margin-left: -295px; .

这会将<div> 向左移动 50%，然后将其负向返回其宽度的一半，从而将其留在中间。

http://jsbin.com/iJESEwe/1/edit?html,css,output