Stick a standard side sheet under the top safe area and the scaffold's sticky app bar

The standard sheet was sticky at `top: 0` and `100dvh` tall, so in an
installed app with a status bar its head row and close button slid under
the status bar once the page scrolled, where the modal sheet already
starts at `--material-safe-top`. Inside `<x-scaffold>` a sticky
`<x-app-bar>` in the `top` slot spans the content region, sheet and all,
and covered it the same way, safe area or not. The sheet now sticks at
`--drawer-top`, the top safe area, or under a scaffold's sticky bar that
safe area plus the bar's 64px row (just the row, if taller than the safe
area, for a medium or large bar, which collapses to it), and is as tall
as the window below that. Every side sheet keeps the bottom safe area
inside its bottom padding. A browser test scrolls a standard sheet in a
scaffold with no bar, a small bar and a large bar at a 47px top and 34px
bottom inset and measures where it sticks, its foot, its close button
and its padding; it fails without the change.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
Andreas Reinhold / reini
2026-09-17 06:06:23 +02:00
co-authored by Claude Opus 5
parent 94a376a4fd
commit 207270a23d
5 changed files with 79 additions and 5 deletions
+3 -1
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@@ -22,7 +22,9 @@
(material-components-android's `SideSheet.md`: "standard side sheet elevation = 0dp,
coplanar"), `surface` rather than surface-container-low, no corner, and an outline-variant
divider down its inner edge in place of the scrim. It sits in the page flow beside the
content, spans the window's height and scrolls on its own; below `expanded` (840px) it is the
content, sticks under the top safe area and under `<x-scaffold>`'s sticky `top` app bar —
as tall as the window below that, with the bottom safe area inside its padding, and scrolls on
its own; below `expanded` (840px) it is the
modal sheet — M3 calls the standard sheet "supplementary surfaces mainly for medium to
expanded breakpoints" and the modal one "preferred at compact breakpoints", and the switch
sits at `expanded` rather than `medium` because M3 also caps a side sheet at 400dp and a