Ok here you go this works I just tested it.

Here is the HTML

<div class="Uniquecontainerholder_colorbackground">
    <div class="msactions_image">[DROPDOWNACTIONS][TITLE]</div>
    <div id="contentpane" class="Purplecontainer_image" runat="server"></div>
    <div>[ACTIONBUTTON:1]</div>
</div>

And here is the CSS

/* Container styles for Image Header Boxes */
.mscontainerholder_transparentbox, .mscontainerholder_colorbackground
{
    border: solid 1px maroon;
    margin-bottom: 10px;
    /* for IE 5.5 */
    height: 1px;
    voice-family: "/")"";
    voice-family: inherit;
    /* for IE 6+ */
    height: 100%;
   
}
.mscontainerholder_transparentbox
{
    background-color: Transparent;
}
.containerholder_colorbackground
{
    background-color: #E9D8D8;
}
.msactions_image
{
    background-color: Maroon;
    border-bottom: solid 1px Maroon;
    padding: 2px 5px;
}
.Purplecontainer_image
{
    padding: 6px 5px 8px 5px;
    color: Purple;
}
.ms_title_imageheader
{
    font: bold 100%, Verdana, Tahoma, Arial, Sans-Serif;
    color: #FFF;
}

As you can see at no point did I overright the .normal class I just defined the text color in my contentpane's class to have a purple font. During my edits I still have black fonts / whatever .normal is set to. However on rendering in the content window it displays as purple text. I tried setting .normal in the skin but it never called .normal for formating the text cause it was only interested in my .Purplecontainer_image style.

Hope that helps.

Let get this right, my CSS I have written in my Module.css will get overwritten by the Default.css which in turn will be overwritten by Skin.css, Container.css and Portal.css

I honestly thought that it worked in completely the opposite way in that Module.css would overwrite all other style sheets...no wonder what I was trying to do doesn't work!!!!

Can someone just confirm this please for my own state on mind.

 I have worked this out, I was appling the colour on the normal tag. 

If I remove this obvioulsy it cant inherit the color from the normal tag, so its all sorted now