Responsive websites are often described as a development model for viewing content on any device, whether it is a large screen with fibre optic connections, or viewing from a mobile phone using very low bandwidth, or even printing via an inkjet printer.
In short, the use cases are so broadly expressed that you never know where, when, what and who will be watching the content. Therefore, we can say that creating a responsive website should prepare content for every situation.
It is almost what, and based on the information sent by the user agent, during the http request and the context of use, the content will be represented and formatted according to the point. The content will be displayed and formatted according to the defined breakpoints, or will be adapted in a fluid way according to the available space.
We speak of adaptive display or responsive display respectively.
As a result, most developers have responded to the solution, which can first meet the needs of mobile devices and add more and more information depending on the available display space. This method is called “mobile first”. In fact, some other developers have reacted differently in the opposite direction, i.e. to provide the best and largest display first and then to reduce the display according to the possibility of the device. This gave rise to two concepts with evocative names: progressive enhancement and graceful degradation.