If you've turned off the plugin and want to work within the new css to accomplish something like the default fluency implementation, give this a try:
//Add to functions.php or, ideally, include in a plugin.
function like_fluency_css() {
echo '<style>
*,body {font-family: helvetica, sans-serif;}
img#header-logo{display: none;}
#adminmenu div.wp-menu-image {float: left;width: 1px;height: 28px;}
#adminmenu .wp-menu-image a{display: none;}
#wp-admin-bar-wp-logo{display: none;}
#adminmenuback, #adminmenuwrap {background-color: #222;border-color: #444;border-right-color: #ddd;}
#adminmenu li.wp-menu-separator {display: none;}
#adminmenu div.separator {border-color: #0e6ac8;}
#adminmenu a.menu-top, .folded #adminmenu li.menu-top, #adminmenu .wp-submenu .wp-submenu-head {border-top-color: #444;border-bottom-color: #000;}
#adminmenu a {color:#fff;}
#adminmenu .wp-submenu a {color:#777;}
#adminmenu a:hover, #adminmenu li.menu-top>a:focus, #adminmenu ul.wp-submenu a:hover {color: #fff;}
#adminmenu li.menu-top:hover>a, #adminmenu li.menu-top.focused>a, #adminmenu li.menu-top>a:focus {background-color: #000;text-shadow: 0 -1px 0 rgba(0, 0, 0, 0.4);}
#adminmenu li.wp-not-current-submenu:hover>a {border-top-color: #000;border-bottom-color: #000;}
#adminmenu li.wp-not-current-submenu .wp-menu-arrow {border-top-color: #000;border-bottom-color: #000;background: #000;}
#adminmenu li.wp-not-current-submenu .wp-menu-arrow div {background: #000;border-color: #000;}
#collapse-menu {color: rgba(255,255,255,0.3);}
#collapse-menu:hover {color: rgba(255,255,255,1.0);}
#collapse-menu:hover #collapse-button {border-color: rgba(255,255,255,0.4);background-color: #333;background-image: -moz-linear-gradient(center bottom , #333, #444);}
#collapse-button {border-color: rgba(255,255,255,0.2);background-color: #000;background-image: -moz-linear-gradient(center bottom , #111, #000);}
#adminmenu .awaiting-mod, #adminmenu .update-plugins, #sidemenu a .update-plugins, #rightnow .reallynow {background-color: #464646;box-shadow: 0 1px 0 rgba(255, 255, 255, 0.5);color: #FFFFFF;}
.folded #adminmenu .wp-submenu-head {border-bottom-color: #ccc;border-top-color: #ccc;}
.folded #adminmenu li.wp-has-current-submenu, .folded #adminmenu li.current.menu-top {border-bottom-color: #6D6D6D;border-top-color: #808080;}
</style>';
}
add_action('admin_head', 'like_fluency_css');
I have not tried nsantillo's solution, but that may be more like what you're after if you're trying to continue to use fluency until it is updated.