How do you "bring in the IntelliJ IDE themes" in a Swing application? The default theme [1] is distinctly lacking in beauty – not because it's not modern, or be

How do you "bring in the IntelliJ IDE themes" in a Swing application? The default theme [1] is distinctly lacking in beauty – not because it's not modern, or because it doesn't have animations, or because it's not native, but because of things like (for example): 1. the inconsistent padding around the focus rectangle (which even touches the outer border on one side!) on that toolbar button to the left in the screenshot, 2. that whoever redesigned the Metal theme some years ago decided to make the selected tab visually connect to the content by using the same background color (good idea, by itself) but apparently didn't notice that every application wraps the content in a widget that draws its own background, resulting in what you see on the screenshot: the tab color continuing for a few pixels into the content and then awkwardly bumping up against the content's background without a border. Also, IntelliJ IDEA has to implement its own menu bar because Swing's built-in one can't do submenus properly. [1] https://upload.wikimedia.org/wikipedia/commons/c/cc/Gui-widgets.png https://upload.wikimedia.org/wikipedia/commons/c/cc/Gui-widg...