Those who deal with interface design have the task of managing what the user of a website or an app sees, and of making it usable for all the navigator’s needs.
The UI designer designs an interface in order to allow the user a satisfying experience, and he works together with the UX designer to define the relationship that the user will have with the final product.
The typography, for example, is an essential element in the construction of the appearance of a digital product, and it is also used as a graphic element: the character in its choice, size, colour, contributes in an essential way to give shape to the contents.
Those who design a website must be aware that the format, colour, contrast and readability of a text will be different, based on what device the user will employ to log in and on the tools that will convey the content message.
Cross-browser incompatibilities can make UI work difficult, which is why standards have been set in some design environments such as Material Design. Material Design is the Android interface that Google applies to its devices, with the aim of providing a common basis for developing optimal websites in all their graphic elements. Responsive design interactions follow precise rules, their animations have to follow mandatory directions in order to trigger expected and foreseeable reactions. If these rules are not respected, there will be a usability deficit that can push the user to leave the page.