We have developed focus mode as a way to test the design's responsiveness inside the editor.
In focus mode, there are no slide dimensions. The page becomes fluid. And you can only see one slide on the screen at the same time (hence the focus part).
We think we have found the sweetest spot between "design" views like the ones on Sketch, Figma, XD ... and browser "focus" views (box paradigm) like Webflow. Best of all is that you can switch instantly between them by clicking on the icons or using the shortcuts "F" for focus or "D" for design.
We also think that there is no faster way to add controlled responsiveness to your projects than using the breakpoint editor in Focus view:
Resize the stage using the slider, create a breakpoint, reorganize the elements in the breakpoint to your taste, change their properties like color, font sizes, visibility, style, media source ... test and create a new breakpoint if needed. Repeat :)