fix(acpmux): saved environments panel rims are one device pixel (hairline-rims base red)

Merged
TE
17d ago
+3-3

Problem

hairline-rims is red on base (seen on #20812 at merge, in a file that PR didn't touch). webviews/src/agent-session/acpmux/savedEnvironments.css, added by #22406, draws three rounded rims at a raw .5px: the environment panel (:14), its name field (:41) and its select (:59). macOS WebKit snaps a sub-pixel rim's inner edge to device pixels but not its rounded clip, so these rims lose edges and corner arcs at 1x and at fractional zoom.

Change

The three rims use var(--cmux-hairline, 0.5px), as the pane's other rims do. The test is unchanged.

Changelog

  • Fixed: The saved environments panel in the New Tab environment picker draws its rounded borders evenly at 1x and at fractional zoom.

Observed / Not run

  • bun test test/hairline-rims.test.ts: base 7fbe5700e80 3 pass, 1 fail (the three lines above). This head: 4 pass.
  • scripts/web-lint.sh: two base reds this PR doesn't touch. check:switch-fetches flags composer/keptAttachments.ts:134 (visibilitychange, from #23139), and HistoryPage.tsx has its prefer-tag-over-role warning (#22966). Pushed with CMUX_WEB_LINT_SKIP_REASON naming both.
  • Not run: a 1x screen capture. CI on this head is pending.

Agent session: huge-blue

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Summary by cubic

Fixes the saved environments panel so its three rounded borders (the panel, its name field, and its select) render evenly at 1x and at fractional zoom.

  • The rims were drawn at a raw .5px, which macOS WebKit clips unevenly; they now use var(--cmux-hairline, 0.5px) as the pane's other rims do.