Don’t know if it is still relevant—or relevant at all, but I don’t believe it’s been mentioned in this post anywhere. You can in Coda have CSSEdit launch by control-clicking a remote CSS file—whatever the file extension. When you do, CSSEdit launches with the remote file in a window.
When you save the CSS in CSSEdit, the file automatically updates remotely, through Coda, in real time—you can see this by saving in CSSEdit wth the Coda file manager not obscured by the CSSEdit window.
Everything updates on the spot. To have CSSEdit launch and integrate with Coda the way I just described, it suffices to add CSSEdit as External editor for CSS in the Preferences.
I am sure all of you know this, because I am absolutely a zero when it comes to programming, scripting and coding, but as I did not see it mentioned anywhere, I thought I’d add it anyway, just in case you weren’t aware…