Weird margin in a list - html

Question

I'm trying to style a menu, but I keep running into this weird margin that's appearing in both FF4 and IE.
This is the only affecting css:
#header ul
{
display: inline;
}
#header ul li
{
list-style-type: none;
background: #000;
display: inline;
margin: 0;
padding: 0;
}
#header ul li a
{
color: #fff;
text-decoration: none;
display: inline-block;
width: 100px;
text-align: center;
}
And this is the HTML:
<div id="header">
<ul id="toplinks">
<li>Hello</li>
<li>Herp</li>
<li>Derp</li>
</ul>
</div>
As you can see, there's a margin appearing on both sides, and I'd like it so it would have no margin (or maybe 1px would be okay)...

Answer 1

That's no moon...i mean...margin.
What you're seeing is the white space between your elements. Inline-block treats the elements as inline, except they have heights, widths, margins, paddings, etc. What happens is the newline + spacing you've given your html elements for nice indentation is being displayed as a space between the elements.
inline-block is also not cross-browser consistent. I'd suggest using display:block; with floats.
Edit to add suggestion:
If you want nice indents, but want to avoid extra white-space (as in all XML data ever), use what I call the "fishy notation"
Instead of:
<div id="header">
<ul id="toplinks">
<li>Hello</li>
<li>Herp</li>
<li>Derp</li>
</ul>
Use:
<div id="header"
><ul id="toplinks"
><li>Hello</li
><li>Herp</li
><li>Derp</li
></ul
></div>
White space contained by elements is preserved, but white space within elements is not.

Answer 2

Time to whip out that CSS Reset! I first include this, and then start designing. It makes it much easier, as most HTML will look identical cross-browser.
But to fix your problem, I would check if there is a stray border property somewhere. I've had rogue borders before, and they drove me mad. To kill it (for now), try this:
border-style: none;
If we had the complete CSS (don't worry, we don't steal it), I could actually fiddle with it and give you a fully functional answer.

Answer 3

change your CSS to
#header ul
{
display: inline;
}
#header ul li
{
float:left;
background: #000;
margin-left: 1px;;
padding: 0;
}
#header ul li a
{
color: #fff;
text-decoration: none;
display: inline-block;
width: 100px;
text-align: center;
}