[8.2] Editing the admin panel

[KyleJ144]

Hi,

 

I have got a couple of issues:

1. I am trying to change the Preston Login Wink image, as when I go to the login button, then it changes to the Preston Login Wink. I have updated the image on staff/themes/default/template/controllers/login but it just won't updated the Preston Login Wink.
2. I have also been trying to change the colour scheme of the backend nav link the colour it displays when the page is active. I have updated the themes.css, override.css and even created custom.css, but nothing seams to be working.
3. I have also been trying to change the logo at the top of the nav menu, but I cannot find what file to edit.

I have been trying all day and i can't seam to get these issues rectified. Any help much appreciated