If set to [adw.types.ToolbarStyle.Flat], top bars are flat and scrolling content has a subtle undershoot shadow when touching them, same as the
.undershoot-top
style class. This works well for simple content, e.g. class@StatusPage or class@PreferencesPage, where the background at the top of the page is uniform. Additionally, windows with sidebars should always use this style.
Undershoot shadow is only present if a top bar is actually present and visible. It is also never present if property@ToolbarView:extend-content-to-top-edge is set to TRUE.
If set to [adw.types.ToolbarStyle.Raised], top bars have an opaque background and a persistent shadow, this is suitable for content such as
utility panes,where some elements are directly adjacent to the top bars, or class@TabView, where each page can have a different background.
[adw.types.ToolbarStyle.RaisedBorder] is similar to [adw.types.ToolbarStyle.Raised], but the shadow is replaced with a more subtle border. This can be useful for applications like image viewers.
See also property@ToolbarView:bottom-bar-style.