The Open Berkeley design is "responsive". This means that when you choose a certain layout for a page and add widgets to different regions within the layout, the widgets will follow a different flow based on the width of the device where they're being viewed (e.g., desktop, mobile, or tablet devices).
About Responsive Behavior of Widgets and Layouts
There are many available layouts when individual pages are customized, and depending on which layout is chosen and how many widgets are used on a page, the widgets will "stack" on smaller displays/mobile devices. See Figure 1, below, for...