I have been using Game Maker (in general) for around 11 years now and Game Maker: Studio for about 4 years. After seeing the same IDE for as long as I have, you start to grow tired of the same interface and visuals. As a result of this I felt inspired to redo a lot of the UI myself and recolor the code editor.
Since the majority of the colors are based on a blue color scheme I have appropriately named this skin Fresh Water.
Making skins in GM:S
My experience making this skin was a bit a frustrating for a few reasons. The biggest complaint I have is that the images are kept inside of a DLL rather than a .ZIP or something a bit more accessible. The positive side of using a DLL is that most people won't take apart the pack and re-distribute it. The other complaint I have is that editing the colors for the IDE is a bit unintuitive. It's hard to see the results of your color choices since you can se the GM:S editor update in real-time.
Where can you get this skin?
I have posted this skin on itch.io for $1. If you are interested, here is a link: