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For those that are familiar with using "Go To Definition" in your code may not be aware that you can use the same technique on for class attributes to go to your CSS definition. It couldn't be easier. Just put your cursor inside the class name:
Then press F12 (or RIGHT CLICK and choose "Go To Definition"). It will instantly take you to the CSS definition and highlight it:
Now you can make edits, etc.. as you see fit.