Costume

Express Theming For Mac

Themeing Software for Mac OS Catalina and Big Sur

About

Costume is a native themeing engine for Mac OS X Catalina and for the upcoming release Mac OS 11 Big Sur.

Costume relies on the modification of system resources stored within Mac OS, specifically the .car system appearance packages.

SIP

On Catalina SIP must be disabled using

csrutil disable

SIP has changed dramatically in Big Sur and no longer allows booting from a live disk. Instead we are booted from a snapshot of the disk that prevents the tampering of system files.

Steps to edit system files on Big Sur

• Create a mount point for the live snapshot
• Make adjustments
• Create new snapshot to boot from
• Reboot

To Do

• Work with SIP enabled (currently requires SIP disabled)
• Decompile .car files on Catalina 10.16.6
• Edit System resources (Port of MILK theme has been completed)
• Complile installer for replacing correct system resources