fix(maestro): make TUI chrome contrast palette-controlled

crates/maestro-tui/src/palette.rs

@@ -106,6 +106,10 @@ pub struct Palette {
     pub card: Surface,
     /// The surface the highlighted card swaps in.
     pub selection: Surface,
+    /// Background for TUI-owned chrome outside cards. Fixed-RGB chrome must
+    /// paint this background too; otherwise its contrast depends on the
+    /// operator's terminal theme.
+    pub chrome_bg: Color,
     /// Panel border while that panel holds focus.
     pub border_focused: Color,
     /// Panel border while it does not.
@@ -148,8 +152,9 @@ impl Palette {
             awaiting: Color::Rgb(0xf2, 0xcc, 0x60),
             error: Color::Rgb(0xff, 0x94, 0x92),
         },
+        chrome_bg: Color::Rgb(0x14, 0x16, 0x1b),
         border_focused: Color::Rgb(0x58, 0xa6, 0xff),
-        border_unfocused: Color::Rgb(0x30, 0x36, 0x3d),
+        border_unfocused: Color::Rgb(0x6b, 0x72, 0x80),
         focus_accent: Color::Rgb(0x58, 0xa6, 0xff),
         group_row: Color::Rgb(0x8f, 0xa3, 0xc8),
         mode_normal_bg: Color::Rgb(0x58, 0xa6, 0xff),
@@ -172,15 +177,18 @@ impl Palette {
     /// Border style for a panel, by whether it holds focus.
     pub fn border_style(&self, focused: bool) -> Style {
         if focused {
-            Style::default().fg(self.border_focused)
+            Style::default().bg(self.chrome_bg).fg(self.border_focused)
         } else {
-            Style::default().fg(self.border_unfocused)
+            Style::default()
+                .bg(self.chrome_bg)
+                .fg(self.border_unfocused)
         }
     }
 
     /// Style for a sidebar group heading.
     pub fn group_row_style(&self) -> Style {
         Style::default()
+            .bg(self.chrome_bg)
             .fg(self.group_row)
             .add_modifier(Modifier::BOLD)
     }
@@ -200,7 +208,7 @@ impl Palette {
 
     /// Style for error text outside a card.
     pub fn error_style(&self) -> Style {
-        Style::default().fg(self.error_text)
+        Style::default().bg(self.chrome_bg).fg(self.error_text)
     }
 }
 
@@ -298,10 +306,13 @@ mod tests {
     }
 
     /// Other panels' roles are RGB too, so a preset swap moves all of them.
+    /// Foregrounds are checked against the chrome background they are
+    /// actually painted on; they must never rely on the terminal default.
     #[test]
     fn chrome_roles_are_rgb_values() {
         let p = active();
         for (name, color) in [
+            ("chrome_bg", p.chrome_bg),
             ("border_focused", p.border_focused),
             ("border_unfocused", p.border_unfocused),
             ("focus_accent", p.focus_accent),
@@ -325,6 +336,19 @@ mod tests {
             let ratio = contrast_ratio(fg, bg).unwrap();
             assert!(ratio >= 4.5, "mode {name} contrast {ratio:.2} is below 4.5");
         }
+        for (name, fg, floor) in [
+            ("border_focused", p.border_focused, 3.0),
+            ("border_unfocused", p.border_unfocused, 3.0),
+            ("focus_accent", p.focus_accent, 3.0),
+            ("group_row", p.group_row, 4.5),
+            ("error_text", p.error_text, 4.5),
+        ] {
+            let ratio = contrast_ratio(fg, p.chrome_bg).unwrap();
+            assert!(
+                ratio >= floor,
+                "{name} contrast {ratio:.2} is below {floor} on chrome_bg"
+            );
+        }
     }
 
     #[test]