It's important that as a developer we also think about the user experience which includes aspects like design, usability, and the overall look & feel in Matomo. This applies not just to the user interface but also to our APIs and the console.
It summarises many elements such as (UI) design, information architecture, usability, accessibility, the look and feel, and more. Learn more about UX.
We try to create an intuitive user interface where a user doesn’t need much training (or none at all) on how to use it.
In Matomo we are using Material Design. You will find a lot of guidelines about colors, typography, iconography, and more. There are also various components shown.
Matomo also includes the Materialize CSS frontend framework.
Open https://matomo.example.org/index.php?module=Morpheus&action=demo&idSite=1&period=day&date=yesterday (replace the domain with your local developer domain) in the browser to find a list of most popular components that can be reused in Matomo. There are also many more components that can be reused that aren't shown there.
nav for a navigation. Use table where it is a table (not div). Use list elements for lists, etc.