Yep, those rules will conflict because in the source it says:
<style type="text/css" media="all">@import "/sites/all/themes/pixture/style.css";</style>
<style type="text/css" media="all">@import "/files/color/pixture-b9f28df3/style.css";</style>These 2 CSS files have almost identical content, without knowing the theme I would assume one is the default and the other is created using the Color module. The proper solution to this would be to fix the theme by only using the colour values in the second stylesheet thus not overriding any rules put into style.css. I could be wrong because I haven't looked into the theme files to know for sure.
If you want a quick fix for now while I/you submit a patch to the theme's issue queue you could add another stylesheet to template.php after the second one above.
Sorry for the short reply, I'm currently out of the office.
Joined: 08/28/2007