I'm not an expert in PHP or coding in any language. I'll clear that up right now. But I will say a few things, seeing how no one has replied to your post yet.
I dont really understand what you mean, but time left. I'm not sure what your ticket tracking system is, but I once worked at an ISP as a support tech, and we wrote tickets there on a webbased system using php, but all it did was record what was wrong with the clients computers and what we tried to fix them. We recorded this information incase our solution didn't fix the clients problem and when they called back, if it wasn't the same tech that helped them before, they could read the ticket to find out what has happened.
So if you reply, please let me know what it is your doing, i'm interested.
So to help you on a technical basis. If you want to change background colors and such, I'm not even sure if thats possible to do dynamically with PHP, as PHP i'm sure you know is server side. So if your running a webserver on the computer that is using your webbased php system, I suppose you could set the page to refresh every so often and check the time. Depending on what the time is, it could set the colours appropriately. This wouldn't be that hard to set up with Apache, as it is free, and install in seconds with php support. But its somewhat impractical.
//check current time and compare with timeleft
//Run this function again in 60 seconds
Of course that was just out of the top of my head, I'm not sure what the actual commands would be, but I'm sure that wouldn't be too hard to set up. You could call the function to change the colours every 5 minutes to check the current times over and over again, so when it finally is time to change the colours, it would.
Hope this helps somewhat. or perhaps I've just mega wasted my time.