Place the tab bar as a sidebar on the inner display

Tab bars were designed for a thumb on a narrow screen. On a regular-width display the same bar leaves a wide, mostly empty strip and pushes navigation to the far bottom edge.

The fix

// SwiftUI
TabView {
    // …
}
.defaultTabBarPlacement(.sidebar)

// UIKit
tabBarController.sidebar.preferredPlacement = .sidebar

This is one of the cheapest visible wins on the whole checklist. The system keeps the tab bar horizontal where that is right — the outer display, compact widths, Split View at a narrow size — and promotes it to a sidebar where there is room.

Design considerations

A sidebar shows labels alongside icons, so review your tab titles. Names chosen to fit under a 60-point icon may read as terse in a sidebar with room for real words.

A sidebar also makes more destinations viable. If you previously collapsed sections into a “More” tab because five was the limit, the inner display can show them directly. Keep the structure identical across placements, though — the same destinations in the same order, laid out differently. Diverging navigation between displays is disorienting when the user folds the device mid-task.

How to verify

Compare the tab bar on the outer display against the inner display. The outer should be a familiar horizontal bar; the inner should be a sidebar with legible labels and the same destinations.