Adopt the new look of macOS

3:45 - Using a monochrome tint for "secondary" sidebar groups

func outlineView(_ outlineView: NSOutlineView, tintConfigurationForItem item: Any) -> NSTintConfiguration? {
  if case let sectionItem as SectionItem = item {
    /* 
       This outline view uses a type called "SectionItem" to populate its top-level sections.
       Here we choose a tint configuration based on a hypothetical `isSecondarySection` property on that type.
     */
    return sectionItem.isSecondarySection ? .monochrome : .default
  }
  // For all other cases, a return value of `nil` indicates that the item should inherit a tint from its parent.
  return nil
}

11:32 - Adopting NSSearchToolbarItem

var searchItem = NSSearchToolbarItem(itemIdentifier: searchIdentifier)
searchItem.searchField = searchField

13:30 - Creating a split view tracking toolbar item

var trackingItem = NSTrackingSeparatorToolbarItem(itemIdentifier: identifier,
                                                  splitView: splitView,
                                                  dividerIndex: 1)

18:39 - Creating a large push button

let button = NSButton(title: "Get Started", 
                      target: self, 
                      action: #selector(finishOnboarding(_:)))
button.controlSize = .large

24:35 - Instantiating a system symbol image

/* 
  Symbol image names are literal descriptions of the symbol glyph, so we must
  include an accessibility description to provide semantic meaning to the image.
 */
let newFolderImage = NSImage(systemSymbolName: "plus.rectangle.on.folder"
                             accessibilityDescription: "New Folder")