If you're unhappy with the default CE4 navigation menu, you may remove it completely from your website. Doing so requires three PHPlugins functions, below.

// KILL THE DEFAULT NAVIGATION MENU
// Using a series of three functions, you can completely gut the 
// default navigation menu. Use this to author your own navigation.

// THIS FUNCTION REMOVES THE NAVIGATION SECTION FROM THE PAGE
function ttg_header_navigation( $style, $path ) { 
	echo '
	
	<!-- put your navigation HTML here -->

	';
	return false;
} // END


// THIS FUNCTION REMOVES THE DEFAULT STYLESHEET FOR OUR NAVIGATION
function ttg_style_navigation( $style, $path ) { 
	echo '
	
	<!-- link to your navigation stylesheet -->

	';
	return false;
} // END

// THIS FUNCTION REMOVES THE R2D2-MENU SCRIPT FROM THE PAGE
function ttg_scripts_navigation( $style, $path ) { 
	echo '
	
	<!-- if your navigation requires Javascript, link your script files here; otherwise, leave this empty -->

	';
	return false;
} // END

You may use these functions to replace the markup, styling and scripts with those of your own design.