The profile header's banner, avatar, and DID drifted to different positions on different devices. SliverAppBar.expandedHeight was hardcoded to 220 while the header content started below a SafeArea whose top inset varies per device (~20pt on older iPhones, ~59pt on Dynamic Island models), so the total height and the content's starting point disagreed: the identity block landed lower and was clipped by a different amount on every screen. Rebuild the header around explicit Positioned layers whose geometry is derived from the device inset and text scale, so the banner's bottom edge always sits a fixed distance below the collapsed app bar and the avatar always straddles that edge by exactly half its height. Note that SliverAppBar computes maxExtent as topPadding + expandedHeight, so expandedHeightFor() deliberately excludes the status-bar inset — including it counts the inset twice and makes the banner grow at twice the inset's rate. Changes: - Derive header geometry from MediaQuery insets and text scale via ProfileHeader.expandedHeightFor / maxExtentFor / collapsedExtentFor - Replace the SafeArea + UnconstrainedBox flow layout with explicit Positioned layers: banner, scrim, avatar, identity - Move bio, stats, and join date into a new ProfileDetails sliver so they are never clipped by the collapsing header, dropping the 2-line bio truncation that the clipping required - Set the banner overhang to avatarSize / 2 so the avatar cannot rise above the collapsed app bar and show through the frosted overlay - Compute collapse progress from the sliver's real max extent, so the frosted blur no longer stalls for the first topPadding px of scroll - Replace the per-platform iOS/Android gradient hacks with one scrim - Make the DID tappable to copy, since it ellipsizes on narrow screens - Add profile_header_test.dart pinning the geometry at insets of 0/20/44/59pt; 3 of its 5 tests fail against the previous layout Verified with flutter analyze, the full test suite (948 passing), and pixel measurements on the Android emulator at two status-bar insets: the banner edge now tracks the inset at 1x (63px between a 24dp and 48dp inset) rather than 2x (126px). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>