Umut, with a card of an icon next to a text as the example: "bei Rows die Breite ändern, am besten per Drag and Drop im Editor". Rows only ever had equal columns - both the classic `columns` token and the free `gridColumns` produce `repeat(n, 1fr)`. A row now carries the free style `columnWidths`, a list of shares such as `2 1` or `66.7 33.3`, per device and without a new document schema. `StyleCompiler::columnTracks()` turns it into `grid-template-columns`, pads or cuts the shares to the number of columns, and gives a device whose layout stacks the columns a single track, because the desktop rule carries an id and would otherwise outrank the class that stacks a phone. In the editor the border between two side-by-side columns of the selected row is a handle: dragging restyles the row inline while the pointer moves and writes one undo step on release; the arrow keys nudge by five points. The design panel shows the same value as the text field "Spaltenbreiten". The Playwright editor check drags the handle with the real mouse. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>