CI: fmt the narrow-layout commits, and Theme::hairline in place of their raw px

src/buttons/segmented.rs

@@ -3,8 +3,7 @@ use std::rc::Rc;
 use gpui::{
     Animation, AnimationExt, AnyElement, App, ElementId, FocusHandle, FontWeight,
     InteractiveElement, IntoElement, MouseButton, ParentElement, Pixels, RenderOnce, Role,
-    ScrollHandle, SharedString, StatefulInteractiveElement, Styled, Window, div, prelude::*, px,
-    rems,
+    ScrollHandle, SharedString, StatefulInteractiveElement, Styled, Window, div, prelude::*, rems,
 };
 
 use super::button::label_size;
@@ -96,7 +95,8 @@ impl RenderOnce for SegmentedControl {
             })
             .collect();
         // Last frame's strip width decides icons only.
-        let strip = window.use_keyed_state((self.id.clone(), "strip-width"), cx, |_, _| Pixels::ZERO);
+        let strip =
+            window.use_keyed_state((self.id.clone(), "strip-width"), cx, |_, _| Pixels::ZERO);
         let shown = *strip.read(cx);
         let compact = self.segments.iter().all(|(_, _, icon)| icon.is_some())
             && shown > Pixels::ZERO
@@ -189,7 +189,9 @@ impl RenderOnce for SegmentedControl {
                     .when_some(icon, |segment, icon| {
                         segment.child(Icon::new(icon).size(icon_size).color(fg))
                     })
-                    .when(compact, |segment| segment.tooltip(Tooltip::text(label.clone())))
+                    .when(compact, |segment| {
+                        segment.tooltip(Tooltip::text(label.clone()))
+                    })
                     .when(!label.is_empty() && !compact, |segment| {
                         segment.child(
                             div()
@@ -246,9 +248,10 @@ fn natural(
     let theme = cx.theme();
     let rem = window.rem_size();
     let (text, icon) = label_size(size);
-    let pad = theme.control_padding(size).to_pixels(rem) * 2.0 + px(2.0);
+    let pad = (theme.control_padding(size).to_pixels(rem) + theme.hairline()) * 2.0;
     let glyph = theme.icon_size(icon).to_pixels(rem) + rems(0.375).to_pixels(rem);
-    segments.iter().fold(px(6.0), |sum, (_, label, icon)| {
+    let strip = (rems(0.125).to_pixels(rem) + theme.hairline()) * 2.0;
+    segments.iter().fold(strip, |sum, (_, label, icon)| {
         let width = text_width(label, text, FontWeight::SEMIBOLD, window, cx);
         sum + pad + width + if icon.is_some() { glyph } else { Pixels::ZERO }
     })

src/forms/switch.rs

@@ -129,7 +129,9 @@ impl RenderOnce for Switch {
             .id(self.id)
             .role(Role::Switch)
             .aria_toggled(self.on.into())
-            .when_some(self.label.clone().or(self.name), |row, label| row.aria_label(label))
+            .when_some(self.label.clone().or(self.name), |row, label| {
+                row.aria_label(label)
+            })
             .when(self.disabled, |row| {
                 row.aria_description(i18n::text(cx, "state.unavailable", &[]))
             })

src/layout/narrow.rs

@@ -18,13 +18,19 @@ pub(crate) fn text_width(
     let font_size = cx.theme().text_size(size).to_pixels(window.rem_size());
     let run = TextRun {
         len: text.len(),
-        font: Font { weight, ..window.text_style().font() },
+        font: Font {
+            weight,
+            ..window.text_style().font()
+        },
         color: Hsla::default(),
         background_color: None,
         underline: None,
         strikethrough: None,
     };
-    window.text_system().shape_line(text.clone(), font_size, &[run], None).width
+    window
+        .text_system()
+        .shape_line(text.clone(), font_size, &[run], None)
+        .width
 }
 
 /// Keeps `width` at the parent's width; a change redraws once.

src/navigation/tabs.rs

@@ -218,7 +218,9 @@ impl RenderOnce for Tabs {
                     .when_some(tab.icon, |item, icon| {
                         item.child(Icon::new(icon).size(IconSize::Sm).color(fg))
                     })
-                    .when(compact, |item| item.tooltip(Tooltip::text(tab.label.clone())))
+                    .when(compact, |item| {
+                        item.tooltip(Tooltip::text(tab.label.clone()))
+                    })
                     .when(!compact, |item| item.child(tab.label.clone()))
                     .when_some(tab.note.clone().filter(|_| !compact), |item, note| {
                         item.child(div().text_color(colors.fg_subtle).child(note))
@@ -293,13 +295,20 @@ impl RenderOnce for Tabs {
 fn natural(tabs: &[Choice], window: &Window, cx: &App) -> Pixels {
     let theme = cx.theme();
     let rem = window.rem_size();
-    let pad = gpui::rems(0.75).to_pixels(rem) * 2.0 + gpui::px(2.0);
+    let pad = (gpui::rems(0.75).to_pixels(rem) + theme.hairline()) * 2.0;
     let glyph = theme.icon_size(IconSize::Sm).to_pixels(rem) + gpui::rems(0.375).to_pixels(rem);
     let gap = gpui::rems(0.25).to_pixels(rem);
     tabs.iter().fold(Pixels::ZERO, |sum, tab| {
-        let text = |text: &SharedString| text_width(text, TextSize::Sm, FontWeight::MEDIUM, window, cx);
-        let note = tab.note.as_ref().map_or(Pixels::ZERO, |note| text(note) + gpui::rems(0.375).to_pixels(rem));
-        let icon = if tab.icon.is_some() { glyph } else { Pixels::ZERO };
+        let text =
+            |text: &SharedString| text_width(text, TextSize::Sm, FontWeight::MEDIUM, window, cx);
+        let note = tab.note.as_ref().map_or(Pixels::ZERO, |note| {
+            text(note) + gpui::rems(0.375).to_pixels(rem)
+        });
+        let icon = if tab.icon.is_some() {
+            glyph
+        } else {
+            Pixels::ZERO
+        };
         sum + pad + icon + text(&tab.label) + note + gap
     })
 }

src/shell/bars.rs

@@ -6,9 +6,9 @@ use gpui::{
 use smallvec::SmallVec;
 
 use crate::{
-    typography::Ellipsis,
     primitives::{Icon, IconName, Tooltip},
     theme::{ActiveTheme, ControlSize, IconSize, Radius, TextSize},
+    typography::Ellipsis,
 };
 
 /// A row of tools, grouped and divided.
@@ -145,7 +145,15 @@ impl RenderOnce for StatusBar {
     fn render(self, _: &mut Window, cx: &mut App) -> impl IntoElement {
         let theme = cx.theme();
         // Narrow, both sides shrink and labels end in an ellipsis.
-        let side = || div().flex().items_center().gap_0p5().h_full().min_w_0().overflow_hidden();
+        let side = || {
+            div()
+                .flex()
+                .items_center()
+                .gap_0p5()
+                .h_full()
+                .min_w_0()
+                .overflow_hidden()
+        };
         self.base
             .flex()
             .flex_none()

src/shell/status.rs

@@ -184,11 +184,18 @@ pub struct ZoomControl {
 
 impl ZoomControl {
     pub fn new(id: impl Into<ElementId>) -> Self {
-        Self { id: id.into(), owned: None }
+        Self {
+            id: id.into(),
+            owned: None,
+        }
     }
 
     /// Shows `percent` and hands each press to `on_zoom`.
-    pub fn owned(mut self, percent: u32, on_zoom: impl Fn(ZoomStep, &mut Window, &mut App) + 'static) -> Self {
+    pub fn owned(
+        mut self,
+        percent: u32,
+        on_zoom: impl Fn(ZoomStep, &mut Window, &mut App) + 'static,
+    ) -> Self {
         self.owned = Some((percent, Rc::new(on_zoom)));
         self
     }
@@ -263,7 +270,11 @@ fn owned(id: ElementId, percent: u32, on_zoom: OnZoom, cx: &App) -> impl IntoEle
         .flex_none()
         .items_center()
         .gap_0p5()
-        .child(IconButton::new("zoom-out", IconName::ZoomOut).size(ControlSize::Sm).on_click(press(ZoomStep::Out)))
+        .child(
+            IconButton::new("zoom-out", IconName::ZoomOut)
+                .size(ControlSize::Sm)
+                .on_click(press(ZoomStep::Out)),
+        )
         .child(
             div()
                 .id("zoom-reset")
@@ -279,7 +290,11 @@ fn owned(id: ElementId, percent: u32, on_zoom: OnZoom, cx: &App) -> impl IntoEle
                 .child(AnimatedNumber::new("zoom-value", percent as f64).size(TextSize::Sm))
                 .child(div().text_size(theme.text_size(TextSize::Sm)).child("%")),
         )
-        .child(IconButton::new("zoom-in", IconName::ZoomIn).size(ControlSize::Sm).on_click(press(ZoomStep::In)))
+        .child(
+            IconButton::new("zoom-in", IconName::ZoomIn)
+                .size(ControlSize::Sm)
+                .on_click(press(ZoomStep::In)),
+        )
 }
 
 #[cfg(test)]

src/theme/tokens.rs

@@ -179,6 +179,11 @@ impl Theme {
         px(1.0)
     }
 
+    /// A border's width, which does not scale: `border_1`.
+    pub fn hairline(&self) -> Pixels {
+        px(1.0)
+    }
+
     pub fn caret_width(&self) -> Rems {
         px_to_rems(1.5)
     }

tasks/github.md

@@ -15,7 +15,7 @@
 
 # GitHub round, 2026-10-08
 
-- [x] G10 CI: `cargo fmt` on the files the last commits left unformatted
+- [x] G10 CI: `cargo fmt` on the files the last commits left unformatted; then the narrow-layout commits: fmt, and `Theme::hairline` for their raw px
 - [x] G11 Issue #7: a caret is a whole number of device pixels wide at a device pixel, so it never shows thin then thick; tested
 - [x] G12 Issue #7: an IME asks for its candidate box past the laid-out text; the box clamps to the last layout, as `bounds_for` does; tested
 - [x] G13 Issue #12: a floating option list occludes, so the wheel scrolls the list and not the page under it; tested