Issue
I had this problem for a long time and I sometimes I would see the CSS changes on my browser sometimes not. All the files get copied to the snapshot folder and the artifact is ok too.There are no possible errors in the IDEA (I'm using intelliJ IDEA Ultimate) or in the code itself.
Solution
For weeks? Try opening the style sheet itself (by entering its address into the browser's address bar) and pressing F5. If it still doesn't refresh, your problem lies elsewhere.
If you update a style sheet and want to make sure it gets refreshed in every visitor's cache, a very popular method to do that is to add a version number as a GET parameter. That way, the style sheet gets refreshed when necessary, but not more often than that.
<link rel="stylesheet" type="text/css" href="styles.css?version=51">
You can add a timestamp instead of version as well which will work in same way for your future css updates. This would work as long term solution for you.
Answered By - Akshay Jain