Inside it, you'll find the files README, Chrome.url, Firefox.xpi, and a .dmg file:
Step 2. Open the .dmg file (named as CSS Pro + version number).dmg
Step 3. Drag and drop the application to your Mac's Applications folder:
Step 4. locate the application via Launchpad or in your Applications folder and click to open it:
Step 5. Follow the application steps to install CSS Pro on your Safari:
Here's a video tutorial:
🎉 Done! Your license is now activated, and you can use CSS Pro anywhere else.
The extension will not ask for your license again (unless deactivated or disabled).