First thank you folks for providing the best source of troubleshooting information. I've fixed pretty much every problem I had with the site I'm working on - except this one pertaining to the menus.

I have the color of the current top-level page set to maroon with white text.
I have the color of the parent of the current submenu page set to the same thing.
I have the submenus set to white with maroon text.

All the styling was done in the custom CSS plugin.

It all works except for one menu item "The Art Gallery". Visit http://www.stjathenaeum.org/WordPress and open any menu with the triangle. They all work except for the Art Gallery.

I've checked that the parent page is set correctly. I took those pages out of the menu and put them back into the menu. I even recreated the page for The Domes of the Yosemite.

Any assistance will be gratefully accepted. Please note that some of the content on the pages looks funky as the site is still in development.

1) you are using '!important' in several places and that overrides other css
2) why not put the CSS in teh themes 'CSS Inserts' option? If you had I could just ask you to export the theme settings and I could try to recreate it and as a bonus, you could get rid of a plugin
3) I see no difference in any of the menu's but I think I know what you are attempting. For instance
if you select the submenu 'Renew/Reserve/ILL', you would like it and it's parent 'The Library' to have a maroon background with white text and have 'The Archives' and 'Library Resourses' to have a white background and maroon text.

Is that correct?

Your description of what I'm trying to do is correct.

I've moved all my CSS to the theme's CSS Inserts. Makes sense.

I have the settings file, but when I try to upload it, I get an error message that my quota has been exceeded. When I click "click here to view your attachments" link I see no way to delete some of the previous attachments. What am I missing?

I figured out how to delete the post to the forum with the big attachment.

Export settings file should now be attached.

Try the following - replace your menu code in the CSS Inserts with the following

div#menu1 ul.rMenu li a:link, 
div#menu1 ul.rMenu li a:hover, 
div#menu1 ul.rMenu li a:visited, 
div#menu1 ul.rMenu li a:active {
    background: #FFFFFF;
    color: #774041;
}

div#menu1 ul.rMenu li.current-menu-ancestor a:link, 
div#menu1 ul.rMenu li.current-menu-ancestor a:active, 
div#menu1 ul.rMenu li.current-menu-ancestor a:hover, 
div#menu1 ul.rMenu li.current-menu-ancestor a:visited, 
div#menu1 ul.rMenu li.current-menu-ancestor {
    background: #774041;
    color: #FFFFFF;
}

div#menu1 ul.rMenu li ul.sub-menu li a:link, 
div#menu1 ul.rMenu li ul.sub-menu li a:active, 
div#menu1 ul.rMenu li ul.sub-menu li a:hover, 
div#menu1 ul.rMenu li ul.sub-menu li a:visited, 
div#menu1 ul.rMenu li ul.sub-menu li {
    background: #FFFFFF;
    color: #774041;
}

div#menu1 ul.rMenu li ul.sub-menu li.current_page_item a:link, 
div#menu1 ul.rMenu li ul.sub-menu li.current_page_item a:active, 
div#menu1 ul.rMenu li ul.sub-menu li.current_page_item a:hover, 
div#menu1 ul.rMenu li ul.sub-menu li.current_page_item a:visited, 
div#menu1 ul.rMenu li ul.sub-menu li.current_page_item {
    background: #774041;
    color: #FFFFFF;
}

because CSS cascades, you have to turn things on and off in the right order

I added the code to CSS Inserts and now nothing changes - every menu is white background with maroon text - main menu, submenu, parent page when on a submenu page, etc. Also I had maroon inverted triangles to indicate that there was a submenu and now they are gone. I did this by replacing the image default image file as per a post on the forum.

What next?