Ok I have looked all over and I am trying to see if there is something I am missing.
Right now I have made a css sheet I like.

So say my welcome page is

HTML Code:
<div id="container"> 
<div id="header"> 
       LOGO 
</div> 
<div id="navbar"> 
   <ul> 
       <li><a>link1</a></li> 
       <li><a>link2</a></li> 
       <li><a>link3</a></li> 
   </ul> 
</div> 
<div id="sidebar"> 
        <span class="custom-button"><a>Link1</a></span>
        <span class="custom-button"><a>Link2</a></span>
        <span class="custom-button"><a>Link3</a></span>
</div>
<div id="content"> 
        Welcome... blah blah
</div>
<div id="footer">
    Unless otherwise stated, the content of this page is licensed 
    under <a href="http://www.gnu.org/copyleft/fdl.html">GNU 
    Free Documentation License.</a>
</div>
</div>
So I use that same layout for all my other pages.

My Question
If I was to change one of the 3 links I would have to go onto every single page and fix them.
Is there an easy way?