The new dark gui was hard to look at.
This thread gave me the idea to finally fix it.
- light grey icon backgrounds everywhere
- option to enable/disable shadow under icons
- replaced dark rubber tiles with inventory background in crafting and logistics windows
- increased size of crafting category icons
- red background for locked slots
- uniform button sounds
- supports flib prototypes
- All these changes have to be made at startup to style prototypes. Factorio sadly does not allow users to set individual skins.