feat(theme): add optional sidebar background

4 files changed, 90 insertions, 1 deletions

diff --git a/src/app/state.rs b/src/app/state.rs
index 7a8837ee..0e1a8439 100644
--- a/src/app/state.rs
+++ b/src/app/state.rs
@@ -107,8 +107,10 @@ use crate::workspace::Workspace;
 pub struct Palette {
     /// Primary accent (highlight, active borders).
     pub accent: Color,
-    /// Background for floating panels, overlays, and modals.
+    /// Background for the tab bar, floating panels, overlays, and modals.
     pub panel_bg: Color,
+    /// Optional desktop sidebar background. Reset preserves the terminal background.
+    pub sidebar_bg: Color,
     /// Subtle surface background for selected/focused items.
     pub surface0: Color,
     /// Slightly lighter surface for hover/active states.
@@ -145,6 +147,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(137, 180, 250), // blue
             panel_bg: Color::Rgb(24, 24, 37),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(49, 50, 68),
             surface1: Color::Rgb(69, 71, 90),
             surface_dim: Color::Rgb(30, 30, 46),
@@ -167,6 +170,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(30, 102, 245),
             panel_bg: Color::Rgb(239, 241, 245),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(204, 208, 218),
             surface1: Color::Rgb(188, 192, 204),
             surface_dim: Color::Rgb(230, 233, 239),
@@ -189,6 +193,7 @@ impl Palette {
         Self {
             accent: Color::Blue,
             panel_bg: Color::Reset,
+            sidebar_bg: Color::Reset,
             surface0: Color::Reset,
             surface1: Color::DarkGray,
             surface_dim: Color::DarkGray,
@@ -211,6 +216,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(122, 162, 247), // blue
             panel_bg: Color::Rgb(26, 27, 38),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(36, 40, 59),
             surface1: Color::Rgb(65, 72, 104),
             surface_dim: Color::Rgb(26, 27, 38),
@@ -233,6 +239,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(46, 125, 233),
             panel_bg: Color::Rgb(225, 226, 231),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(196, 200, 218),
             surface1: Color::Rgb(168, 174, 203),
             surface_dim: Color::Rgb(210, 211, 218),
@@ -255,6 +262,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(189, 147, 249), // purple
             panel_bg: Color::Rgb(40, 42, 54),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(68, 71, 90),
             surface1: Color::Rgb(98, 114, 164),
             surface_dim: Color::Rgb(40, 42, 54),
@@ -277,6 +285,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(136, 192, 208), // frost
             panel_bg: Color::Rgb(46, 52, 64),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(59, 66, 82),
             surface1: Color::Rgb(67, 76, 94),
             surface_dim: Color::Rgb(46, 52, 64),
@@ -299,6 +308,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(215, 153, 33), // yellow
             panel_bg: Color::Rgb(40, 40, 40),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(60, 56, 54),
             surface1: Color::Rgb(80, 73, 69),
             surface_dim: Color::Rgb(40, 40, 40),
@@ -321,6 +331,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(7, 102, 120),
             panel_bg: Color::Rgb(251, 241, 199),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(235, 219, 178),
             surface1: Color::Rgb(213, 196, 161),
             surface_dim: Color::Rgb(242, 229, 188),
@@ -343,6 +354,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(97, 175, 239), // blue
             panel_bg: Color::Rgb(40, 44, 52),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(44, 49, 58),
             surface1: Color::Rgb(62, 68, 81),
             surface_dim: Color::Rgb(40, 44, 52),
@@ -365,6 +377,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(64, 120, 242),
             panel_bg: Color::Rgb(250, 250, 250),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(240, 240, 241),
             surface1: Color::Rgb(229, 229, 230),
             surface_dim: Color::Rgb(245, 245, 246),
@@ -387,6 +400,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(38, 139, 210), // blue
             panel_bg: Color::Rgb(0, 43, 54),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(7, 54, 66),
             surface1: Color::Rgb(88, 110, 117),
             surface_dim: Color::Rgb(0, 43, 54),
@@ -409,6 +423,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(38, 139, 210),
             panel_bg: Color::Rgb(253, 246, 227),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(238, 232, 213),
             surface1: Color::Rgb(147, 161, 161),
             surface_dim: Color::Rgb(238, 232, 213),
@@ -431,6 +446,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(126, 156, 216), // blue
             panel_bg: Color::Rgb(31, 31, 40),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(42, 42, 55),
             surface1: Color::Rgb(54, 54, 70),
             surface_dim: Color::Rgb(31, 31, 40),
@@ -453,6 +469,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(77, 105, 155),
             panel_bg: Color::Rgb(242, 236, 188),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(220, 213, 172),
             surface1: Color::Rgb(201, 203, 209),
             surface_dim: Color::Rgb(213, 206, 163),
@@ -475,6 +492,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(196, 167, 231), // iris
             panel_bg: Color::Rgb(25, 23, 36),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(31, 29, 46),
             surface1: Color::Rgb(38, 35, 58),
             surface_dim: Color::Rgb(38, 35, 58),
@@ -497,6 +515,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(144, 122, 169),
             panel_bg: Color::Rgb(250, 244, 237),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(242, 233, 225),
             surface1: Color::Rgb(255, 250, 243),
             surface_dim: Color::Rgb(242, 233, 225),
@@ -519,6 +538,7 @@ impl Palette {
         Self {
             accent: Color::Rgb(255, 199, 153),
             panel_bg: Color::Rgb(26, 26, 26),
+            sidebar_bg: Color::Reset,
             surface0: Color::Rgb(35, 35, 35),
             surface1: Color::Rgb(40, 40, 40),
             surface_dim: Color::Rgb(16, 16, 16),
@@ -570,6 +590,9 @@ impl Palette {
         if let Some(c) = &custom.panel_bg {
             self.panel_bg = parse_color(c);
         }
+        if let Some(c) = &custom.sidebar_bg {
+            self.sidebar_bg = parse_color(c);
+        }
         if let Some(c) = &custom.surface0 {
             self.surface0 = parse_color(c);
         }
@@ -2398,6 +2421,31 @@ mod tests {
     }
 
     #[test]
+    fn built_in_themes_leave_sidebar_background_unset() {
+        for name in THEME_NAMES {
+            let palette = Palette::from_name(name).unwrap();
+            assert_eq!(
+                palette.sidebar_bg,
+                Color::Reset,
+                "built-in theme changed the sidebar background: {name}"
+            );
+        }
+    }
+
+    #[test]
+    fn custom_sidebar_background_overrides_the_default() {
+        let custom = crate::config::CustomThemeColors {
+            sidebar_bg: Some("#181825".to_string()),
+            ..Default::default()
+        };
+
+        assert_eq!(
+            Palette::catppuccin().with_overrides(&custom).sidebar_bg,
+            Color::Rgb(24, 24, 37)
+        );
+    }
+
+    #[test]
     fn light_theme_aliases_resolve() {
         for name in ["light", "latte", "tokyo-day", "onelight", "lotus", "dawn"] {
             assert!(
diff --git a/src/config/theme.rs b/src/config/theme.rs
index fc601d3f..e98c9dfb 100644
--- a/src/config/theme.rs
+++ b/src/config/theme.rs
@@ -32,6 +32,7 @@ pub struct ThemeConfig {
 pub struct CustomThemeColors {
     pub accent: Option<String>,
     pub panel_bg: Option<String>,
+    pub sidebar_bg: Option<String>,
     pub surface0: Option<String>,
     pub surface1: Option<String>,
     pub surface_dim: Option<String>,
@@ -164,6 +165,7 @@ name = "nord"
 
 [theme.custom]
 panel_bg = "#1e1e2e"
+sidebar_bg = "#181825"
 accent = "#ff79c6"
 red = "rgb(255, 85, 85)"
 "##;
@@ -171,6 +173,7 @@ red = "rgb(255, 85, 85)"
         assert_eq!(config.theme.name.as_deref(), Some("nord"));
         let custom = config.theme.custom.as_ref().unwrap();
         assert_eq!(custom.panel_bg.as_deref(), Some("#1e1e2e"));
+        assert_eq!(custom.sidebar_bg.as_deref(), Some("#181825"));
         assert_eq!(custom.accent.as_deref(), Some("#ff79c6"));
         assert_eq!(custom.red.as_deref(), Some("rgb(255, 85, 85)"));
         assert!(custom.green.is_none());
diff --git a/src/main.rs b/src/main.rs
index da905311..b6cc62b8 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -128,6 +128,7 @@ const DEFAULT_CONFIG: &str = r##"# herdr configuration
 # Override individual color tokens on top of the base theme.
 # Accepts: hex (#rrggbb), named colors, rgb(r,g,b), or panel_bg = "reset"
 # [theme.custom]
+# sidebar_bg = "#181825"
 # panel_bg = "reset"
 # accent = "#f5c2e7"
 # red = "#ff6188"
diff --git a/src/ui/sidebar.rs b/src/ui/sidebar.rs
index 50796e81..7ce1b0ad 100644
--- a/src/ui/sidebar.rs
+++ b/src/ui/sidebar.rs
@@ -757,6 +757,9 @@ pub(super) fn render_sidebar_collapsed(app: &AppState, frame: &mut Frame, area:
     let is_navigating = matches!(app.mode, Mode::Navigate);
 
     let p = &app.palette;
+    frame
+        .buffer_mut()
+        .set_style(area, Style::default().bg(p.sidebar_bg));
     let sep_style = if is_navigating {
         Style::default().fg(p.accent)
     } else {
@@ -960,6 +963,9 @@ pub(super) fn render_sidebar(
     area: Rect,
 ) {
     let p = &app.palette;
+    frame
+        .buffer_mut()
+        .set_style(area, Style::default().bg(p.sidebar_bg));
     let is_navigating = matches!(app.mode, Mode::Navigate);
     let sep_style = if is_navigating {
         Style::default().fg(p.accent)
@@ -1592,6 +1598,37 @@ mod tests {
     }
 
     #[test]
+    fn expanded_and_collapsed_sidebars_use_custom_background() {
+        let mut app = crate::app::state::AppState::test_new();
+        app.workspaces.clear();
+        app.active = None;
+        app.palette.sidebar_bg = ratatui::style::Color::Rgb(12, 34, 56);
+        let area = Rect::new(0, 0, 26, 20);
+
+        let mut expanded = Terminal::new(TestBackend::new(26, 20)).unwrap();
+        expanded
+            .draw(|frame| render_sidebar(&app, &TerminalRuntimeRegistry::new(), frame, area))
+            .unwrap();
+        assert!(expanded
+            .backend()
+            .buffer()
+            .content
+            .iter()
+            .all(|cell| cell.bg == app.palette.sidebar_bg));
+
+        let mut collapsed = Terminal::new(TestBackend::new(26, 20)).unwrap();
+        collapsed
+            .draw(|frame| render_sidebar_collapsed(&app, frame, area))
+            .unwrap();
+        assert!(collapsed
+            .backend()
+            .buffer()
+            .content
+            .iter()
+            .all(|cell| cell.bg == app.palette.sidebar_bg));
+    }
+
+    #[test]
     fn default_agent_rows_remove_redundant_state_text() {
         let mut app = crate::app::state::AppState::test_new();
         let workspace = Workspace::test_new("one");