I just returned home and immediately checked the Pixture theme. It seems from the README.txt that you might need to visit the theme settings page and resave the settings:

Due to the mechanism of recoloring by the color module, your changes to the style sheet (style.css) in the theme directory does not take effect until you save the theme setting from the theme setting page. It would be easy to change the color scheme to the default scheme (= Girly Pink) and work on the style sheet changes. If you do so, the changes you are going to make to the style sheet would take effect immediately when you reload the current page from the web browser.