change GNOME 3.36 gdm3 lock screen (screen shield) font colour - what css selector to target in gdm3.css?

I am aware from other posts that you can change e.g. the login screen background by modifying the css selector #lockDialogGroup in gdm3.css that you get when extracting the .gresource binary.

What is the equivalent for changing the clock / time font in the lock screen (screen shield)? I tried changing .unlock-dialog-clock and .unlock-dialog-clock-time but to not much result. Am I targetting the right selectors?

EDIT after discussion:

My workflow is as follows:

extract / edit / compile in ~/.local/share/gnome-shell/theme/Pop-modified, which is under version control (see below):

To apply the changes, I run the following command:

sudo cp ~/.local/share/gnome-shell/theme/Pop-modified/gnome-shell-theme.gresource /usr/share/gnome-shell/theme/Pop-modified/gnome-shell-theme.gresource

which is where gdm3-theme.gresource is pointing to, using update-alternatives (see below):

➜ update-alternatives --config gdm3-theme.gresource
There are 3 choices for the alternative gdm3-theme.gresource (providing /usr/share/gnome-shell/gdm3-theme.gresource).

  Selection    Path                                                                   Priority   Status
------------------------------------------------------------
  0            /usr/share/gnome-shell/theme/Pop/gnome-shell-theme.gresource            20        auto mode
  1            /usr/share/gnome-shell/gnome-shell-theme.gresource                      10        manual mode
* 2            /usr/share/gnome-shell/theme/Pop-modified/gnome-shell-theme.gresource   0         manual mode
  3            /usr/share/gnome-shell/theme/Pop/gnome-shell-theme.gresource            20        manual mode

The actual edits are done as follows:

• Rename gdm3.css and gnome-shell.css to gdm3-original.css and gnome-shell-original.css respectively.

• Create new files called gdm3.css and gnome-shell.css, import the original css files and make all desired changes to these files.

Currently, the edits I made under #lockDialogGroup is in effect but not those under .unlock-dialog-clock.

GNOME shell version:

➜ gnome-shell --version
GNOME Shell 3.36.3

Contents of /usr/share/gnome-shell/modes:

➜ ls /usr/share/gnome-shell/modes
initial-setup.json  pop.json  ubuntu.json

/* Screen Shield */
.unlock-dialog-clock {
  color: green;
  font-weight: 300;
  text-align: center;
  spacing: 24px;
  padding-bottom: 2.5em; }