You can change the appearance of the H4W BOSS interface by clicking on the H4W Configuration Tab and then Configure Color Theme.
On this screen you can change the appearance by choosing the element you want to change and then clicking on the color from the color wheel that you want that element to be. For example you can click on the Background option and then chose a color. You also can choose from some default themes.
After you have changed the color theme make sure to click the Save Color Theme button.