It's kinda like a second language to some coders. Different languages have different syntaxes.
CSS is all about styling elements. Just from that, we need to know two things: the element to style and the styling to apply.
Syntax:
element {
Styling}
Styling is usually of this syntax:
styling_name:
styling_value;
styling_name2:
styling_value2;
So, first off, we need to know the element to manipulate. There are different ways of doing this. We can reference a general type of element (i.e. td, tr, table, div), a class (i.e. .windowbg, .windowbg2, .catbg), or an ID (i.e. #forumjump). There's a few other things (like selectors), but I won't be covering them. It's not worth confusing you right now.
Just know that you must use a:link instead of a.
Alright, so let's select an element and add some styling. First thing is to grab an element.
.windowbg {
styling here}
So that'll modify any element that has a class of "windowbg." How do we know it's a class and not an ID or element? Easy. Classes are ALWAYS prefixed with a period. IDs are ALWAYS prefixed with an ID. Elements NEVER have a prefix. However, elements can have a suffix.
td.windowbg {
styling here}
That'll select all TD's with a class of "windowbg" Note that I didn't put a space. Putting a space completely changes the meaning. This is the next thing. If you put a space between two elements, you're saying that the first is a parent element of the second. So, if we had this HTML source:
<table class="whee">
<tr>
<td id="dude">
<font class="whee">
Test
</td>
</tr>
</table>
putting this would style the table:
table.whee {
styling here}
while putting this would style the font tag:
font.whee {
styling here}
and this would also style the font tag: (NOTE THE SPACE)
td .whee {
styling here}
Also, the PARENT does not have to be a PARENT, it can be a GRANDPARENT or GREATGRANDPARENT element. (Caps are just fun, no?). So, tr .whee refers to the same element as td .whee in this case.
The last thing to mention is that you can have multiple specifications listed for a styling set.
td .whee, font, table.whee {
styling here}
Those would all receive the same styling. Notice how they're separated by commas? Yeah, that's how you do it.
As for the actual styling... your best bet is to look at some CSS sources and find some parameters they use so you can see some you can use.