Introducing Cascadea, the first custom style manager designed as a Safari App Extension and native macOS app. Cascadea makes it easy to install custom styles that change the look and feel of any website you want. Whether you want your social media feed to burst with color, or to give your eyes a break with a darker style, Cascadea gives you the freedom to paint the web in your colors.

Installing styles is easy - you can easily import styles from popular custom style websites, or import any CSS file from a URL or local file. Once installed, Cascadea has a clean, simple user interface for quickly toggling or deleting styles. Since Cascadea is built with a fast, fluid native UI, it's easy to mass-toggle or mass-delete styles, drag them around to organize your style list, or export and import entire databases of styles.

Cascadea is also an incredibly powerful tool for CSS developers, whether you're writing custom styles of your own or using it as part of your web development workflow. Cascadea includes a fully-featured code editor for writing custom stylesheets, with support for autocompletion, syntax highlighting, automatic indentation, code folding, beautification, multicursor support, and more. Choose between multiple color themes for the editor, open multiple styles in tabs, and watch Safari update live when you save changes. Plus, if you prefer your own code editor, you can easily export and import a standard CSS file into and out of Cascadea.

Other features include:
• The fastest, cleanest UI of any custom style manager.
• Full support for Dark Mode in macOS Mojave.
• Sync your styles and preferences across multiple Macs using iCloud.
• Tie styles to your macOS (10.14.4+) system appearance - Dark Mode-ify websites when you want, and seamlessly change themes when you don't.
• Automatically update styles imported from a URL.
• Easily duplicate imported styles to edit a local copy without it being overwritten by an update.
• Exclude websites from styles to prevent conflicts or override global styles.
• Customize variables in UserCSS-format custom styles.
• Write and use styles written either in standard CSS or the Stylus preprocessor language.
• Change the injection order of styles by just dragging and dropping entries in your style list.
• Export your entire style collection to a single database file, and import them back just as easily.
• Open Cascadea quickly or toggle your styles with a click of a button in your Safari toolbar.
• Touch Bar support on equipped MacBook Pro models.
• No user tracking. At all. Ever. Cascadea collects absolutely no data from you, outside of opt-in anonymized crash reports provided by Apple through the App Store.

What’s New

Version 1.5.5

• Added option to disable the Safari extension’s toggle shortcut (Ctrl+D) in Cascadea’s Preferences.

Ratings and Reviews

5.0 out of 5
1 Rating

1 Rating

Mr Knieves ,

Just what I was looking for

I love this app but I'm giving it 4 stars because it could have a better tutorial or instructions on how to import themes from userstyles.

Also, and if it's not clear, you CAN import themes from userstyles. Just look for the theme you want, once there look for "Install style as userscript", copy that URL and import it on Cascadea.

Other than that I really love that I can modify my favorite sites so my eyes dont bleed, and also now I can finally get rid of Chrome.

Developer Response ,

Thanks for using Cascadea!

For importing styles from the Userstyles website, there's actually an easier method - when viewing a style, you should simply see a button to "Install in Cascadea" in the upper right corner of the page. This should also support (most) customization options for styles there as well.

- Mike

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.

Ejhandeland ,

I'm sure it works well

I'm sure it works for most people, however if you try to specify a domain on a specific port the styles wont load. I was trying to stylizes a few pages on my server but since they all have the same address but diffrent ports their wasnt a way to style them.

Developer Response ,

Sorry for the trouble you're having styling sites on your server! While "Domain" rules don't allow for you to distinguish different ports, you should be able to use "URL starts with" rules to target specific ports, like "" and "". This should also be possible using regular expression rules. If neither of those work for you, please email me at so I can look into this further!


Mike Freuden
17.3 MB

macOS 10.13 or later, 64-bit processor



Age Rating


  • Family Sharing

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