Confused about overriding CSS styles - css

Question

I understand CSS basics, but I keep running into trouble with conflicting styles. Consider the following styles.
First, the default font color in my style sheets is black. I want that color applied to all picture captions - unless they're contained in divs with a class CoolL or CoolR...
.CoolL .Caption, .CoolR .Caption { color: #900; }
Now all the captions in the Cool series have brown text. But there are situations where I want the captions to have a black background with white text, so I created this rule:
.Black { background: #000; color: #fff; }
Now consider the following HTML. Class Caption by itself should have black text. However, this is inside a div with a class CoolR, so it displays brown text instead. But I added the class Black to the last div, which should change the background to black and the text color to white...
<div class="CoolR Plus Max300">
<div class="Shadow2">
<img src="">
<div class="Caption Black">Text</div>
</div>
</div>
In fact, the background is displaying black, but the text color is still brown.
I get these problems all the time, and the only way I can fix them is to write long, detailed styles, like this...
.Black, .Caption .Black, .CoolR .Caption.Black, .EverythingElseThatCouldBeBlack .Black { background: #000; color: #fff; }
What am I missing? Thanks.

Answer 1

I think you are over complicating things. This will become a maintenance issue as you add more styles. I would define separate classes and keep things simple. It's also important to understand CSS specificity.
.caption {
color: #000;
}
.cool-caption {
color: #900;
}
.caption-with-background {
background-color: #000;
color: #fff;
}

Answer 2

You could try :
.Black { background: #000 !important; color: #fff !important; }

Answer 3

There are a few fixes, but as previously recommended you should mark all of the settings you want to override previous ones with !important. With that, your code would look like this:
.Black {
background: #000;
color: #fff;
}
Also, not sure if you asked this, but you can apply CSS to all components by using the *, like so:
* {
//blahblahblah
}

Answer 4

you are defining the first case with a descendant selector which overrides the second class, which is merely a class. every answer given already will work but are entirely unnecessary. just add this to your style sheet:
.CoolR1 .Black, .Black{ background: #000; color: #fff;}
/** you could also chain your classes for specificity power **/
.Black.Caption{color:#fff}
that should do it. you can read more about selectors here:
http://docs.webplatform.org/wiki/css/selectors

Answer 5

I think that generally a more specific rule overrides a more general one, thus the more specific '.CoolR .Caption' is overriding the more general .Black. You'll probably be able to override this with !important, but a better style might be to reduce the complexity of your rules:
.Cool .caption { color: #900; }
.Cool .caption.black { color: background: #000; color: #fff; }
And put .L and .R in separate classes
.Cool.L { . . . } /* For things specific to CoolL, but not CoolR */
.Cool.R { . . . } /* and vice-versa */