Menu Bar on Mobile Site

Hello I have just switched my company's webpage over to your catch responsive theme to make it more mobile friendly. But when I access our site via a mobile device the menu button in the top left corner is very hard to see as it is three gray lines on a darker background. I know the easy solution is to choose a lighter background to contract with it, but is there any way to change the coloring of those three bars that denote the menu? qes.com is the website