fix: keep explorer selections readable on light terminals

docs/development.md

@@ -131,6 +131,7 @@ Diff LSP integration checks reuse the real framed-protocol subprocess with test-
 
 Changed-file explorer checks cover reuse of the compact directory tree, removed/historical paths, file-to-directory transitions, remapped tree/selection bindings, filter/open/focus transitions, right-dock geometry, and wheel routing without edits to the underlying document.
 Visibility checks preserve browsing and pane state across Ctrl+e, exclude hidden explorers from focus/wheel routing, and verify full-width review. Status checks preserve catalog associations through sorting, compaction, duplicate inputs, and file/directory collisions, and cover colored A/M/D/R markers, selected/unfocused rows, Tree/List filtering, and sanitized rename paths.
+Light-terminal explorer selection checks render focused/unfocused rows through theme changes, require readable filename/status/directory contrast on Pumpkin Light, and retain dark/unknown-terminal fallbacks. A live PTY check answers native OSC color queries, opens the explorer with Space e, and observes the pale truecolor selection without changing source bytes.
 Diff styling checks cover independent snapshot language/shebang/injection detection, accepted/stale snapshot identity, real-parser cache freshness/reuse/release, syntax foreground over changed backgrounds, real empty rows versus missing counterparts, scrolling-stable diagonal hatching, and tab/wide/combining/control-character clipping. TestBackend omits wide-glyph continuation cells; terminal smoke verifies their actual styling.
 
 ## Performance and process limits

docs/editing.md

@@ -297,6 +297,9 @@ Pane-focus bindings also work while the ordinary file explorer or picker has foc
 
 Floating windows overlay the entire editor, above all workspace panes. File pickers, revision selectors, hover documentation, and completion lists are not clipped to the focused pane; completion remains anchored to its caret. Docked exploration reserves space at the editor edge before the remaining workspace is split into panes. The changed-file explorer follows the same layout, on the editor's right edge.
 
+On light terminals that answer color queries, selected explorer rows use a pale shade of the terminal background, preserving filename, directory and repository-status foregrounds when focused or unfocused. Dark terminals and unavailable color reports retain the ANSI blue/dark-gray selection backgrounds. Theme changes update visible and parked panes.
+
+
 Diff comparisons reuse the split geometry and directional-focus engine. Option/Alt navigation moves between Before, After, and Files first, then to a neighboring workspace pane when there is no internal target in that direction. Splitting a diff text view creates an ordinary sibling showing the same buffer; historical snapshots remain read-only, including after the comparison closes.
 
 ## Tabs

src/tui.rs

@@ -484,9 +484,22 @@ impl BufferViewports {
         }
         self.theme = theme;
         let colors = DiffColors::new(theme);
+        let file_selection_background = theme.and_then(|theme| {
+            let [r, g, b] = theme.background.map(u32::from);
+            if r * 299 + g * 587 + b * 114 < 128_000 {
+                return None;
+            }
+            // Keep ANSI status/directory foregrounds readable on light terminals.
+            let [r, g, b] = theme
+                .background
+                .map(|c| ((u16::from(c) * 95 + 50) / 100) as u8);
+            Some(Color::Rgb(r, g, b))
+        });
         self.panels.diff_colors = colors;
+        self.panels.file_selection_background = file_selection_background;
         for pane in self.parked.values_mut() {
             pane.panels.diff_colors = colors;
+            pane.panels.file_selection_background = file_selection_background;
         }
     }
 
@@ -542,6 +555,7 @@ impl BufferViewports {
             })()
             .unwrap_or_default();
             inherited.panels.diff_colors = self.panels.diff_colors;
+            inherited.panels.file_selection_background = self.panels.file_selection_background;
             self.parked.insert(id, inherited);
         }
         let outgoing = self
@@ -5699,6 +5713,7 @@ struct WheelPanels {
     picker_scroll: PickerScroll,
     diff: Option<DiffGeometry>,
     diff_colors: DiffColors,
+    file_selection_background: Option<Color>,
     diff_syntax: Option<DiffSyntaxCache>,
     previous_diff: Option<DiffGeometry>,
     diff_wrap: Option<DiffWrapViewport>,
@@ -6380,11 +6395,13 @@ fn draw_file_list(
                 };
                 if selected {
                     style = style
-                        .bg(if picker.focused {
-                            Color::Blue
-                        } else {
-                            Color::DarkGray
-                        })
+                        .bg(panels
+                            .file_selection_background
+                            .unwrap_or(if picker.focused {
+                                Color::Blue
+                            } else {
+                                Color::DarkGray
+                            }))
                         .add_modifier(Modifier::BOLD);
                 }
                 let changed = entry

tests/unit/tui.rs

@@ -32,6 +32,74 @@ impl Drop for Directory {
     }
 }
 
+#[test]
+fn explorer_selection_follows_light_background_and_restores_dark_styles() {
+    let directory = Directory::new();
+    directory.file("arguments.hon", "return 0\n");
+    let mut picker =
+        FilePicker::from_paths(directory.0.clone(), [(0, PathBuf::from("arguments.hon"))]);
+    let light = ThemeColors {
+        background: [255, 246, 230],
+        red: [177, 52, 37],
+        green: [82, 101, 31],
+    };
+    let dark = ThemeColors {
+        background: [31, 23, 20],
+        red: [224, 120, 100],
+        green: [169, 182, 101],
+    };
+    let mut views = BufferViewports::default();
+    let mut terminal = Terminal::new(ratatui::backend::TestBackend::new(70, 12)).unwrap();
+    for theme in [Some(light), Some(dark), None, Some(light)] {
+        views.set_theme(theme);
+        for focused in [false, true] {
+            picker.focused = focused;
+            terminal
+                .draw(|frame| {
+                    draw_file_list(frame, &picker, frame.area(), "", &mut views.panels, None);
+                })
+                .unwrap();
+            let buffer = terminal.backend().buffer();
+            let cell = buffer
+                .content
+                .iter()
+                .find(|cell| cell.symbol() == "a" && cell.modifier.contains(Modifier::BOLD))
+                .expect("selected arguments.hon row");
+            if theme == Some(light) {
+                let Color::Rgb(r, g, b) = cell.bg else {
+                    panic!("light selection must not use a dark ANSI background");
+                };
+                let luminance = |rgb: [u8; 3]| {
+                    rgb.into_iter()
+                        .zip([0.2126, 0.7152, 0.0722])
+                        .map(|(c, w)| {
+                            let c = f64::from(c) / 255.0;
+                            w * if c <= 0.04045 {
+                                c / 12.92
+                            } else {
+                                ((c + 0.055) / 1.055).powf(2.4)
+                            }
+                        })
+                        .sum::<f64>()
+                };
+                for foreground in [[69, 49, 38], [138, 98, 28], [153, 91, 43]] {
+                    assert!((luminance([r, g, b]) + 0.05) / (luminance(foreground) + 0.05) >= 4.5);
+                }
+                assert_ne!([r, g, b], light.background, "selection must remain visible");
+            } else {
+                assert_eq!(
+                    cell.bg,
+                    if focused {
+                        Color::Blue
+                    } else {
+                        Color::DarkGray
+                    }
+                );
+            }
+        }
+    }
+}
+
 #[allow(clippy::too_many_arguments)]
 fn rendered_whitespace_line(
     source: &str,