Changing the color to something custom will take some work. Here is a CSS example you can start with:

body.red #main-top,
body.red #main-bottom,
body.red div.feature-top,
body.red div.feature-bottom,
body.red div#cat-nav,
body.red div.feature-sidebar h2 {
	background-image: url("http://s0.wp.com/wp-content/themes/premium/traction/stylesheets/../images/colors/green/sprite-bg.png");
}
body.red .nav ul {
    background-image: url(http://s0.wp.com/wp-content/themes/premium/traction/images/colors/green/nav-bottom.png);
}
body.red .nav li li {
	background: #207b1d;
}
body.red .nav li li:hover,
body.red .nav li li.sfhover,
body.red .nav li li.current_page_parent,
body.red .nav li li.current_page_ancestor,
body.red .nav li li.current-cat-parent,
body.red .nav li li.current-cat,
body.red .nav li li.current_page_item {
	background: #1b6b19;
}
body.red div#feature {
	background-image: url(http://s0.wp.com/wp-content/themes/premium/traction/images/colors/green/feature-body.png);
}
body.red .nav a {
	color: #c04d4d;
}

Copy each url() value, save the corresponding image, recreate a new image with the colors you want, upload the new image you created to your media library, copy the link URL, replace the url() value for the image in the CSS example above with the link URL of your custom image.

Also note that the example above uses "body.red" and that means it depends on the theme using the red color scheme option. If you change the color scheme in the theme options, you will also need to update the "body.red" CSS rule to match.

how did you change the category and the pages bar?

Can someone please share the css code for changing the standard "red" menu bar colour to something different please. I am using Premium "Traction" Theme.

Thanks

Also note what airodyssey posted. You paid for a premium theme and included in that purchase is support for theme issues provided to you in the Premium Themes Forum.

This article explains how to do what you're trying to do quite well: http://ourthemes.blog.com/traction-featured-slider/

Regardless, if you really have your heart set on Traction, I'd still recommend contacting Staff because of the messed up aspect ratio. Another thing I noticed is that there are no "previous" and "next" buttons for easy navigation between Gallery attachment pages. Just FYI

I don't want to eliminate the sidebar entirely.

Unfortunately, it seems that there is no example of a Gallery post on the demo site.

http://en.forums.wordpress.com/forum/premium-themes

Are there any Traction users that are aware of any other settings or is 600 pixels the maximum photo width that can be used.