Start with the simple answer.

Safari Web Extensions are packaged inside a macOS app. The app installs the extension and gives you a visible place to confirm its status; the extension supplies the browser toolbar and UserCSS features.

Applying CSS requires access to the webpages you choose. StylePort uses that permission to match a page and insert your selected CSS. It does not use the permission to create or transmit a browsing history.

Styles, variables, and preferences live in Safari’s local extension storage on your Mac. StylePort has no account or developer-operated cloud database.

StylePort is built on the mature Stylus engine and the migration path for compatible backups is part of the release work. Always keep your original backup until a restore has been verified.

Yes. The signed direct edition is available, and the public TestFlight beta remains open for testing the Apple-distributed edition on a Mac running macOS 14 or later. Join the StylePort TestFlight beta.

The direct-download edition uses Sparkle with a signed update feed and Ed25519 verification. You can check manually or choose automatic checks while the StylePort companion app is open; automatic installation stays off. The App Store edition uses Apple’s update system and does not include Sparkle.

The first release targets macOS Safari. An iOS and iPadOS container is on the roadmap after the Mac experience and release process are reliable.