Welcome to Cascadea, the native custom style extension designed exclusively for macOS and Safari. Cascadea lets you customize practically any website using custom CSS themes. Make your social media feed pop with your favorite colors. Give that super-bright website a darker theme that's easier on the eyes. Cascadea gives you the freedom to paint the web in your own colors.

It's super easy to install styles - just go to a compatible style in Safari, and you'll see an option to install it in Cascadea. Cascadea supports popular custom style websites, styles written in the UserCSS format, or even plain CSS files. Once installed, Cascadea's fast native UI lets you quickly and easily configure settings for each style, change the order in which they apply, keep them up to date, and more.

Cascadea is also a super-powerful tool for CSS developers, both for writing new custom styles or even as part of a web development workflow. Cascadea has a fully-featured Style Editor for writing both CSS and the Stylus preprocessor language, including autocompletion, syntax highlighting, automatic indentation, code folding, beautification, multi-cursor support, multiple color themes and font options, and more. Open multiple styles in tabs, configure rules for precisely which sites to apply a style, and watch Safari update to reflect your changes each time you save your CSS. Or, if you prefer your own code editor, you can easily import a CSS file into and out of Cascadea.

Other features include:
• Sync your styles and preferences seamlessly across multiple Macs with iCloud.
• Tie styles to your macOS system appearance - have your Dark Mode styles when you want them, and automatically turn them off when you don't.
• Configure variables in compatible UserCSS-format styles.
• Write and install styles written in either standard CSS, or the Stylus preprocessor language.
• Easily import and export your entire style database from Preferences.
• See which styles are active on a page right from Cascadea's toolbar icon in Safari, and double-click to open a style right in the Style Editor.
• Have Cascadea automatically update your imported styles on launch.
• Exclude specific sites from a style to prevent conflicts or override a global style.
• Native support for Macs with Apple silicon (such as Apple's M1).
• Support for the Touch Bar on MacBook Pro.
• No user tracking - period. Cascadea collects no data, outside of opt-in anonymous crash reports provided by Apple.

What’s New

Version 2.0.5

• Updated internal version of Stylus-lang to resolve issues with certain styles.
• Addressed a bug where a certain portion of the Style List may not respond to clicks.
• Addressed a bug where variables in Style Properties may not show their label after choosing to reset all variables to their defaults.

Ratings and Reviews

4.6 out of 5
34 Ratings

34 Ratings

Starfia ,


So often I've wanted to tweak just one element of a web site in Safari (darkening Daring Fireball's background or setting that circular font on Twitch to San Francisco, for example) without sketchy cross-platform extensions with questionable reputations.

Cascadea is finally it; built for this precise purpose in the most Mac-like way possible. Inexpensive, the ideal lightweight interface with a lightweight CSS editor, no bugs after months of use, support for Stylus (my preferred choice of alternative), and updates are ready when Apple is.

Some apps, you kind of regret buying even if they're good. Not this one.

MarqueIV ,

Works perfectly!

What a great little gem! As a developer, I was about to write my own extension for Safari, but then I came across this. It's close to perfect! It allowed me to easily customize the sites to fit my reading/viewing habits. Only a couple minor things I'd change that I'm thinking about writing the author on, but realistically, even in its current form, it still deserves a 5/5, which is what I gave it. Excellent job! Highly recommended!

Cowboy_X ,

this is what CSS was for

Excellent little app. Kudos to the devleoper for keeping it going despite the never-ending changes in Apple's Extensions requirements.

An important goal of the original CSS spec was for user-defined stylesheets to be "the norm." The idea was that people would style with personal accessibility and taste in mind. Though I'm unsurprised that this goal has turned out to be mostly impractical, user-defined CSS is still and important and worthwhile funciton, and Cascadea delivers it to us.

App Privacy

The developer, Mike Freuden, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer's privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More


Mike Freuden
19.3 MB

macOS 10.14 or later



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.