To add a background to the tab content I implement the following background, nesting another modifier equal within this one.
.background(
.background // ERROR: Ambiguous use of 'background'
.shadow(.drop(
color: .primary.opacity(0.08),
radius: 5, x: 5, y: 5)
)
.shadow(.drop(
color: .primary.opacity(0.08),
radius: 5, x: -5, y: -5)
),
in: .capsule
)