WebPutty is fast and powerful CSS editor and service online application. It is free and to start your project you just need to login with your Google credentials.
I must admit that I am not overconfident when I am working with cascading style sheets; this process requires patience, knowledge and most likely a lot of tweaking for different browsers. A while ago I found this web application which is platform independent, this mean that you can use in your browser on Mac, Windows or Linux.
I like WebPutty as it gives me this confidence that I am lacking and to be accurate I like to see live preview of CSS. The interface is simple and intuitive, side-by-side editing environment, Web Putty, gives you selector highlighting, SCSS extensions, such as variables and mixings and recently become popular Compass authoring framework (compass-style.org). Tricks, such as being able to use variable to describe your color set, make coding much easier.
I really favor the capability that WebPutty hosts your CSS files and serves them zipped and minified and of course can export files on your own. The service is free for early adopters, but most likely will be launched in pay version in the future.
Overall, WebPutty does work very well and make CSS coding simpler, the only thing that it lacks for now is code completion and hinting which can make work even simpler than it is.
To start up, visit the official website: https://www.webputty.net/