任何人都可以檢查我的CSS代碼的下拉菜單，不能集中導航菜單？

Question

我是新的編碼CSS，試過建議的答案有關我的問題，但沒有任何作品，任何幫助將不勝感激;我希望把我的菜單頁面的中心，同時保持容器背景覆蓋整個可用寬度...

這裏是我的html代碼：

<div id="nav"> 
    <li><a href="index.htm">Home</a></li> 
    <li><a href="about.htm">About</a> 
     <ul> 
      <li><a href="history.htm">History</a></li> 
      <li><a href="about.htm#mission">Mission</a></li> 
      <li><a href="about.htm#bod">Board of Directors</a></li> 
      <li><a href="location.htm">Location</a></li> 
     </ul> 
    <li><a href="SFO.htm">Facilities & Services</a> 
     <ul> 
      <li><a href="#">Services >></a> 
       <ul> 
        <li><a href="im.htm">Internal Medicine</a></li> 
        <li><a href="obg.htm">OB-Gyne</a></li> 
        <li><a href="pedia.htm">Pediatrics</a></li> 
        <li><a href="surgery.htm">Surgery</a></li> 
        <li><a href="dental.htm">Dental Care</a></li> 
        <li><a href="rehab.htm">Rehabilitation Medicine</a></li> 
        <li><a href="ent.htm">Otorhinolaryngology(ENT)</a></li> 
       </ul> 
      <li><a href="facilities.htm">Facilities >></a> 
       <ul> 
        <li><a href="lab.htm">Laboratory-Tertiary Level</a></li> 
        <li><a href="i&cc.htm">Intensive & Critical Care</a></li> 
        <li><a href="nnc.htm">Nursery & Neonatal Care</a></li> 
        <li><a href="picu.htm">Pediatric Intensive Care</a></li> 
        <li><a href="pcu.htm">Pulmonary Care</a></li> 
        <li><a href="ecc.htm">Ear Care Center</a></li> 
        <li><a href="hdu.htm">Hemodialysis Unit</a></li> 
        <li><a href="cardio.htm">Cardiac Diagnostics</a></li> 
        <li><a href="rd.htm">Radiology Diagnostics</a></li> 
        <li><a href="obg.htm">OB-Gyne Diagnostics</a></li> 
       </ul> 
    </ul> 
    </li> 
    <li><a href="hp.htm">Healthcare Plans</a> 
    <ul> 
      <li><a href="hmo.htm">Accredited HMOs</a></li> 
      <li><a href="executive.htm">Executive Checkup</a></li> 
      <li><a href="cc.htm">Credit Cards</a></li> 
    </ul> 
    </li> 
    <li><a href="hcp.htm">Doctors</a> 
     <ul> 
      <li><a href="#">""</a></li> 
     </ul> 
    </li> 
    <li><a href="career.htm">Careers</a></li> 
    <li><a href="archive.htm">Archive</a></li> 
    <li><a href="faq.htm">FAQ</a></li> 
    <li><a href="faq.htm">Contact Us</a></li> 
     </ul> 
    </li> 
</ul> 
</div> 

和我的CSS代碼：

#nav { 
    Z-INDEX: 10; 
    text-align:center; 
    width: 100%; 
    height: 20px; 
    background: green; 
    position: relative; 
    padding:3px; 
    font-size: 13px; 
    list-style-type:none; 
    list-style-position:outside; 
    display:inline-block; 
    font-weight: bold; 
    line-height:1.5em; 
    float: none; 
} 
#nav-wrapper { 
    text-align: center; 
} 
#nav ul{ 
    Z-INDEX: 10; 
    text-align:center; 
    position:relative; 
    width: 1000px; 
    display:inline-block; 
    margin:0; 
    padding:0; 
    background: none; 
    list-style-type:none; 
    list-style-position:outside; 
    line-height: 1.7em; 
    font-size: 13px; 
    float: none; 
} 

#nav li li{ 
    Z-INDEX: 10; 
    text-align:left; 
    display:inline-block; 
    margin:0; 
    padding:0; 
    font-weight: normal; 
    list-style-position:outside; 
    border-bottom: 0.1em solid white; 
    color: #fff; 
} 

#nav a:link, #nav a:visited{ 
    display:block; 
    padding:0px 5px; 
    color:#fff; 
    text-decoration:none; 
    background: green; 
} 

#nav ul a:hover{ 
    Z-INDEX: 999; 
    background: light-green; 
    color: yellow; 
    position: relative; 
} 

#nav li ul a:hover{ 
    Z-INDEX: 999; 
    background: green; 
    color: yellow; 
    position: relative; 
} 

#nav li li a:hover{ 
    Z-INDEX: 999; 
    background: light-green; 
    color: yellow; 
    font-weight: bold; 
    position: relative; 
} 

#nav li a:hover{ 
    background: light-green; 
    color: yellow; 
    Z-INDEX: 999; 
    position: relative; 
} 

#nav a:active{ 
    color: yellow; 
    font-weight: bold; 
} 

#nav li{ 
    float:left; 
    position:relative; 
} 

#nav ul { 
    position:absolute; 
    width:14em; 
    top:1.3em; 
    display:none; 
} 

#nav li ul a{ 
    width:14.65em; 
    float:left; 
} 

#nav ul ul{ 
    top:auto; 
    } 

#nav li ul ul { 
    left:14.65em; 
    margin:0px 0 0 10px; 
    } 

#nav li:hover ul ul, #nav li:hover ul ul ul, #nav li:hover ul ul ul ul{ 
    display:none; 
    } 
#nav li:hover ul, #nav li li:hover ul, #nav li li li:hover ul, #nav li li li li:hover ul{ 
    display:block; 
    } 

Answer 1

你可以包住#nav與另一div。

<div id="wrap"> 
    <div id="nav"></div> 
</div> 

的width從#nav刪除，並應用下面的CSS：

#wrap { 
    background: green; 
    text-align: center; 
} 

jsFiddle here - 它的工作原理。