WARNING TO THOSE WHO ATTEMPT TO USE MY MACOS MOJAVE THEMES ON MACOS CATALINA!!! DONT' USE THEM WITH MACOS CATALINA 10.15.5.
NONE OF YOUR APPS WILL OPEN - NOT FINDER, NOT TERMINAL - SO YOU'LL HAVE TO ROLL INTO RECOVERY MODE TO FIX. BUT, THAT'S POINTLESS IF THERE'S NO BACKUP OF THE MACOS CATALINA .CAR THEME FILES INCLUDED.
UPDATE.. SAFE TO USE WITH MACOS MOJAVE 10.14.3 AND LATEST ITUNES RELEASE FOR MACOS MOJAVE - CHECKED ON THE 12th of MARCH 2019
These are the .car files that I copied from my Sierra.
I'm not sure what files are needed.
In Sierra there is no .car file for DarkAquaAppearance but only DarkAppearance files.
I'm certain that you have done everything correct - I'm just curious about the situation since it works on my Mac.
I'm using latest macOS Mojave 10.14.5. I have yet to try using the iTunes .car files.
Also, often you don't have to restart - just a logout. the replacements files are system wide but a logout should suffice in case you are experimenting.
There's nothing changed apart from the window titlebar controls.
Would you mind zipping(7zip, rar?) the whole lot of .car files you have from that latest beta of Mojave and share it somewhere online for me to take a look?
I can build you and everyone else a version for the beta. Give me a day or two after that.
Or I could enroll myself in the beta - that is of course another option.
There are two things you would need to do before installing this theme, or any theme.
Step 1: Disable SIP; which is System Integrity Protection. This is not something many are willing to do but for the purpose of changing a theme you would have to turn it off.
You can turn SIP on again afterwards but if you have the desire to roll back to default macOS theme, SIP would have to turned off again. All I'm saying is that it takes a lot of reboots.
SIP is turned off by using this command in the Terminal on your Recovery Partition: csrutil disable. Likewise is the command for turning SIP on again: csrutil enable
Step 2: Make a backup of the existing files in /System/Library/CoreServices/SystemAppearance.bundle/Contents/Resources/
The best way to get to this location is by using the Go -> Go To Folder menuitem within the Finder app. Just copy the whole path above into the window that you are presented with.
You should exclude the en.lproj folder therein for this purpose of backing up.
Step 3: The third step is to copy in the files in the archive on this page to the same directory as the one you already are in for the purpose of making backups of the existing macOS theme files.
Note for step 3: An Administrator code is required for copying files to this location.
Step 4: For each app to take on the appearance of the theme they must be reopened - you could just logout - but for testing the theme you can just open a program like Safari or Notes app on macOS to see the appearance.
Step 4.1: And if you don't like the appearance of this new theme then while you have the Finder and it's path to the theme files open, just copy back ALL the .car files from your backup.
Note.. the files that has the extension .car are essentially the theme files. And I encourage everyone to have a backup of all the existing .car files and I also encourage everyone to copy ALL the .car files from their backup back instead of just the changed ones. At least when the themes are from me.
Note.. SIP (SystemIntegrityProtection) is there to protect the user. But also annoy we who like to do a little more with our systems. I can make no guarantees that the themes will continue to work with later macOS Mojave versions and certainly not what's coming in the soon to be 10.15 macOS versions to be announced at WWDC in June of 2019.