Explain Mostly fluid pattern for creating responsive design
In mostly fluid pattern a web page with the multi-column layout structure doesn't change its core layout until the smallest visual breakpoint occurs. The core structure of web page remains same at large, medium and small devices. The structure of page changes at the smallest device and multi-column layout web page's column stacked vertically down.
In above diagram web page starts with 3 column structure. Web page structure remains same for large, medium and small devices. The structure changes at smallest screen size and column stacked vertically down.