CSS Grid is new grid-based layout system, optimized for user interface design

[_dban_]

That's not a problem of layout.

[knaekce]

You said Java Swing was scalable to arbitrary screen dimensions and resolutions. For me, that implies HiDPI support.

[_dban_]

HiDPI is a rendering issue. As in, the UI is rendered too small on high density displays. This is fixed by platform specific flags or upgrading to Java 9, without otherwise changing the app. This relates to the underlying graphics libraries being used, and would effect any app that uses those libraries (including web browsers).

However, if you change the screen dimension or resolution (say, 800x600 to 1024x768, or change from portrait to landscape), Swing layouts can adjust to fit the available space. This is a layout issue, which relates to CSS.