The AccentColor and AccentColorText system colors can be used in CSS to access the system accent color specified on the user's device. This allows developers to apply native app like styling to their web content in contexts where users expect OS theme integration, such as an installed web application. Users must be in an installed web application on the initial profile to see the system accent color rendered.
Without access to system accent colors, developers must hardcode theme values or implement non‑native design patterns, resulting in web applications that visually diverge from user‑configured platform settings. This is especially noticeable in installed web apps, where users expect a level of OS‑level visual integration comparable to native applications.