Looking for logging into the Gnome 3 Highlight Color site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Gnome 3 Highlight Color site. After that you can login as usual with your login credentials.
https://askubuntu.com/questions/682708/how-to-set-a-custom-text-highlighting-colour
https://www.reddit.com/r/gnome/comments/6vgut8/is_there_an_easy_way_to_change_the_adwaita/
https://ubuntuforums.org/showthread.php?t=2001319
https://help.gnome.org/users/gnome-terminal/stable/app-colors.html.en
https://github.com/Ubuntu/gnome-shell-communitheme/issues/54
https://bugs.launchpad.net/bugs/1725536
http://discourse.ubuntu.com/t/changing-the-grub-splash-and-gdm-lock-screen-color/7516
https://www.ostechnix.com/how-to-change-gdm-login-screen-background-in-ubuntu/
https://ask.fedoraproject.org/en/question/7046/how-can-i-change-the-background-of-the-gnome-login-screen/
https://www.gnome-look.org/p/1013747/
https://unix.stackexchange.com/questions/133914/set-gnome-terminal-background-text-color-from-bash-script
https://mike632t.wordpress.com/2016/05/28/gnome-3-customizing-the-login-screen/
https://wiki.manjaro.org/index.php?title=Change_the_colours_of_your_GTK%2B_themes