HsHon, this is how I managed to change the clock color (there's probably a better/quicker technique but whatever):

On you phone, copy the libsysuid-screenlock-nokia.css to a folder visible when in USB Mass Storage mode (for example: /home/user/MyDocs/Documents/). I used File Manager to perform this step.

Now, connect your N9 to the computer and navigate to the folder where you copied the css file.

Edit the file using a text editor, not Word :-) I use Notepad++

The line you want to change is line 85 in my file, two lines below: LockScreen MLabelStyle#LockScreenLowPowerModeClockLabel {

I suggest using basic red(#FF0000) blue(#0000FF) green(#00FF00). I noticed some other colors also work but not all of them.

Once your done editing save the file and eject your device.

On the phone's terminal:

type in:
You then need to type in your password, default is rootme I believe.
EDIT: I'm not sure this is necessary but I'm not a pro with these user permission things hehe. It works this way and that's enough for me.

We then need to copy the edited file from the "Documents" folder back to the original folder.

type in:
Reboot your device. If you don't see the clock anymore it's probably because you chose a non-supported color.

You can edit the file directly on the device in the terminal but I find this technique easier. If anyone has a better way of doing this please let me know. Could we somehow add something in the settings pane for this?

oSCho