CSSEdit does not have support for SCSS or SASS files at all. But it is possible to hack it.
Go in to your Applications folder right click on the app and select Show Package Contents.
Locate the file called info.plst and open it using Coda (or any other Editor).
Look for CFBundleTypeExtension where you will see an array with a string node called CSS. Copy that line and add the SCSS or SASS or both extensions.
Save the file, Restart the app. You can now open SCSS files.
Note: CSSEdit has no idea how to handle the SCSS syntax so don’t expect the Styles or attribute editor to be 100% accurate,
I noticed if you have any nested properties CSSEdit will pick up other attributes until the next closing }
I hope that some day CSSEdit will natively support SASS and will be merged into Espresso.
Lately at work we have been using SASS for our new web app Inkdit. Sass has been a blessing as well as a curse.
Aside from the benefits of SASS we have been using another extension of SASS called SCSS, Read more on the benefits of SASS here.
One Editor that I have been using occasionally is Sublime Text and while it’s not my favorite it is a great text editor.
After manually changing the syntax mode from plain text to CSS on all of my SASS files I had a look for a package. I found that Sublime Text supports many languages and supports some of TextMate syntax highlighting files.
Then I did some hacking and was able to add the SCSS extension with little trouble at all.
Follow these steps:
Preferences > Browse Packages
Download sublime-text-haml-sass from Github and copy the two folders into the Package folder.
Open the SASS folder, Under Syntax’s open up SASS.tmLanguage
Save, restart Sublime Text and Enjoy!