customize a spreadsheet hyperlink style

I can’t seem to find in any of the style managing/modifying dialog’s a way to customize the look of a simple hyperlink within a cell that I’d converted from a plain text string. Neither the cell styling or text styling will allow me to remove the ugly grey background (see attached image) behind each text character in the string.

Thanks in advance.

2012 Macbook Pro / OS X / El Cap
LO: Version:

Please take a look if this options to change the color for visited and unvisited links helps.

image description

Thanks, but I had tried that area previously. Using the Application Colors dialog, the url text color will change just fine, (which why its that particular shade of green in my screenshot), but the grey background remains unfortunately.