How Do I Change the color of YouTube Buttons Inside?

[koolx]

Hey guys!! Please look at the attached pic. In the top right corner, you'll see circled in red the button in youtube called, 'Sign In'. The button is blue, but the inner partof the button is in dark grey. I want to change this inner part to blue also to make the button a solid blue.

 

When I used Inspect Element, I isolated the code that changes the color of this inner part of the button. The code is below:

 

|*.guide-item.guide-item-selected |span, |*.yt-uix-button-subscribe-branded |*.yt-uix-button-content |span, |*.yt-uix-button-subscribed-branded |*.yt-uix-button-content |span, |*.yt-uix-button |span {color: #FFFFFF !important;background-color: transparent !important;}

But I tried to change the color by adding, "background-color: transparent !important;". But that doesn't work. I don't know exactly if this is the right code to use or not. Let me know what I should do.. Thanks!!