Hello, It is not possible to change its color because it is an image not a color If you want to change its color then, Go to images directory present in your theme directory and replace your image with present tab images or edit it. The name of image is 1."tbg.png" 2."slider-sepnew.png" 3."slidertextbgnew.png" Note:- Use same name for your edited image and remove the current image.
