Css - Navigation menu <Ul> - Sub Menus

Question

I am currently developing a site and I am trying to get into more css coding, I have go the basic css for the navigation done. Although what I want to do now is Make sub menus, so when you roll over one of the buttons the menus appear.

Here's my current Css: HTML Code:

/*Naviagtion Bar Css */
ul {
    margin: 0;
    padding: 0;
    list-style:none;
}
li {
padding-top:5px;
color: #FFF;
width:120px;
float: left;
margin: 0;
padding: 0;
}
li a {
    display: block;
    width: 120px;
    height: 30px;
    padding-top:20px;
}
#homepage a {
    background-image: url(../images/Button_NavBar_Unselected.png);
    background-repeat: no-repeat;
}
#homepage_current a {
    background-image: url(../images/Button_NavBar_CurrentPage.png);
    background-repeat: no-repeat;
}
#homepage a:hover {
    background-image: url(../images/Button_NavBar_Hover.png);
    background-repeat: no-repeat;
}

#guide a {
    background-image: url(../images/Button_NavBar_Unselected.png);
    background-repeat: no-repeat;
}
#guide_current a {
    background-image: url(../images/Button_NavBar_CurrentPage.png);
    background-repeat: no-repeat;
}
#guide a:hover {
    background-image: url(../images/Button_NavBar_Hover.png);
    background-repeat: no-repeat;
}

#blog a {
    background-image: url(../images/Button_NavBar_Unselected.png);
    background-repeat: no-repeat;
}
#blog_current a {
    background-image: url(../images/Button_NavBar_CurrentPage.png);
    background-repeat: no-repeat;
}
#blog a:hover {
    background-image: url(../images/Button_NavBar_Hover.png);
    background-repeat: no-repeat;
}

#media a {
    background-image: url(../images/Button_NavBar_Unselected.png);
    background-repeat: no-repeat;
}
#media_current a {
    background-image: url(../images/Button_NavBar_CurrentPage.png);
    background-repeat: no-repeat;
}
#media a:hover {
    background-image: url(../images/Button_NavBar_Hover.png);
    background-repeat: no-repeat;
}

#forum a {
    background-image: url(../images/Button_NavBar_Unselected.png);
    background-repeat: no-repeat;
}
#forum_current a {
    background-image: url(../images/Button_NavBar_CurrentPage.png);
    background-repeat: no-repeat;
}
#forum a:hover {
    background-image: url(../images/Button_NavBar_Hover.png);
    background-repeat: no-repeat;
}
#navbar {
    position:relative;
    top:5px;
    float:left;
    margin-top:30px;
    margin-left:45px;
    width:600px;
    height: 50px;
    z-index:-1;
}

Html Code:

<div id="navbar" style="display: inline-block;">
<ul>
   <li id="homepage_current"><a><strong>Home</strong></a></li>
   <li id="guide"><a><strong>Guide</strong></a>
      <ul>
         <li> Sub Menu 1 </li>
         <li> Sub Menu 2 </li>
         <li> Sub Menu 3 </li>
      </ul>
   </li>
   <li id="blog"><a><strong>Blog</strong></a></li>
   <li id="media"><a><strong>Media</strong></a></li>
   <li id="forum"><a><strong>Forums</strong></a></li>
</ul>
</div>

Any help would be appreciated. Here's a link to the page.

Answer 1

The way to do it, first, you have to set the parent element relative like this

#navbar>ul>li{position:relative;}

then set the child element to be under the parent(And make it hidden) (20 px is arbitrary)

#navbar>ul>li>ul{position:absolute;top:20px;left:0px; display:none;}

then make the submenu visible on hover

#navbar>ul>li:hover>ul{display:block;}

Also, i would suggest to change your current style for li's to #navbar>ul>li, since the li css will affect also all the submenu

And beware of the > operator, it is not supported in a lot of old navigator IE6 & IE5, if that is important, use :

<li id="guide" class="lvl1"><a><strong>Guide</strong></a>

and style with :

li.lvl1{...

Answer 2

As long as you don't have any specific problem i suggest you one of the may tutorials that are out there. For example the probably the most famous one: Suckerfish! It's a perfect start.
Or perhaps this could also help you along.

Finally, here is a tutorial on how to create a nice CSS3-Dropdown.

Also CSS-Dropdown menus have been talked about several times here on Stackoverflow.