Position Fixed Doesn't Work

Question

I want to make my topmenu stay on fixed position. I know i have to use position:fixed property but it doesnt work. Seems like after i put position:fixed top:0 on id topmenu it's overlapping with my below content. here i put my code here is my site desawisataserang.com

HTML

<div id="topmenu">
<ul class="menu">
<li class="item-464 active"></li></ul>
  <div id="search">    
  <div class="search">
  </div>
    </div>
  </div>

CSS

#topmenu {
  margin: auto;
  width: 1000px;
  padding-left: 0px;
  font-family: :"Segoe UI", "Segoe WP", "Helvetica Neue", 'RobotoRegular', sans-serif; font-weight: 400;
  font-size: 1.2em;
  color: #fff;
  background-color: #c02929;
  overflow: auto;
}

#topmenu ul { 
  float: left;
  padding: 18px;
  padding-top: 0px;
  padding-bottom: 0px;  
  margin: 0;
  list-style: none;
  background-color: #c02929;
}

#topmenu a {
  display: block;
  color: #fff;
  padding-top: 14px;
  padding-bottom: 14px;
  padding-left: 24px;
  padding-right: 24px;
  margin-left: 0px;
  margin-right: 0px;
  margin-bottom: 0px;
  text-decoration:none;
  text-transform: uppercase;
}

#topmenu a:hover {
  color: #000;
  text-decoration: none;
  display:block;
  background-color:#525252;
}


#topmenu li { 
  float: left;

}

#topmenu li:first-child { 
  border-left: 0px solid #000000;
}

Answer 1

When you give position: fixed the element rendering isn't considered when rendering other elements on the page. You have to give padding-top for your body, so that it doesn't overlap with the header.

For your site example, try these:

#topmenu {
  position: fixed;
  width: 1000px;
  z-index: 100;
  overflow: none;
  left: 50%;
  margin-left: -500px;
}

Answer 2

Add padding-top: to body. padding top value will be height of you top menu

Css:

       body {
            padding-top: 50px;
        }

        #wrapper {
        display: block;
        padding: 0;
        min-width: 1000px;
        text-align: center;
        width: 100%;
        position: fixed;
        top: 0;
        z-index:9999;
}

    #topmenu {
      margin: 0 auto;
      width: 1000px;
      padding-left: 0px;
      font-family: :"Segoe UI", "Segoe WP", "Helvetica Neue", 'RobotoRegular', sans-serif; font-weight: 400;
      font-size: 1.2em;
      color: #fff;
      background-color: #c02929;
      overflow: auto;
    }

Html:

<div id="wrapper">
<div id="topmenu">
<ul class="menu">
<li class="item-464 active"></li></ul>
  <div id="search">    
  <div class="search">
  </div>
    </div>
  </div>
</div