CSS experts, please show me what I'm missing... [SOLVED]

Question

I want to know how Firefox knows the difference between certain code surrounding Arch's stuff. For instance, the time and date stamp above every post here. This is an example:
<h2><span><span class="conr">#1 </span><a href="viewtopic.php?pid=674509#p674509">2009-12-19 12:26:19</a></span></h2>
and from the wiki:
<a name="Getting_Started" id="Getting_Started"></a><h2> <span class="mw-headline"><a href="/index.php/Getting_Started" title="Getting Started">Getting Started</a></span></h2>
Both of these pick up on the h2 settings I have in a CSS file that I'm putting together:
h1,h2 {
font-family:"DejaVu Sans" !important;
font-weight:bold !important;
font-size:14px !important;
Firefox doesn't apply the bold settings to the first example but does to the second. This is exactly what I want. If I add another entry:
h2 span {
font-family:"DejaVu Sans" !important;
font-weight:normal !important;
font-size:13px !important;
Then the bold goes off on both of them. I want a generic CSS file that has the time and date normal and the wiki entries bold. Firefox does this automatically. What am I missing?
... be back in 20 hours ...

Answer 1

Mh, I'm sure you know about the tree structure of HTML. Please excuse if tell you things you already know, but allow me to talk about how CSS rules are applied.
<h2>
<span>
<span class="conr">#1 </span>
<a href="viewtopic.php?pid=674509#p674509">2009-12-19 12:26:19</a>
</span>
</h2>
What CSS does is applying the CSS rules for each element/selector. This means first it will apply the rules for h2, then the rules for span and at last the rules for the class conr or the element a respectively. If any properties already exists, they will be overwritten when applying the rules of a more specific element. If multiple rules apply (for instance multiple classes with conflicting properties), the !important will help the browser to decide which rule to apply.
In your case I guess that there are rules for the class conr or the span element which conflict with your desired setting. Since you only change the rules for h2, the rules of those more inner elements/attributes take precedence.