Adapting an app to run on different device types,
such as mobile and desktop, requires dealing
with mouse and keyboard input, as well as
touch input. It also means there are different
expectations about the app’s visual density,
how component selection works
(cascading menus vs bottom sheets, for example),
using platform-specific features (such as
top-level windows), and more.

Creating a responsive Flutter app

Flutter allows you to create apps that self-adapt
to the device’s screen size and orientation.

There are two basic approaches to creating Flutter
apps with responsive design:

LayoutBuilder class