Use default color in default theme for light-theme terminals (#16509)

Closes #16477
Closes #15847

Change the default theme to use the ANSI default color (`39m`) instead
of white (`37m`).
The goal of this is to improve readability on light-theme terminals.

I tested this change across **5 dark themes** (Catppuccin Mocha, Ayu
Mirage, Tokyo Night, Dracula, Apprentice) and **5 light themes**
(Catppuccin Latte, Gruvbox Light, Solarized Light, Tokyo Night Day,
Paper Color Light), in both **foot** and **alacritty** terminals.

- On most dark themes, there is little to no visual difference
(sometimes slightly better contrast).
- On light themes (e.g. Solarized Light), switching to the default color
makes text significantly more readable.

I attached a screenshot below using Solarized Light in alacritty.  
The left side is using white color while the right side shows the new
change using default color:

<img width="1351" height="507" alt="Comparison of white vs default color
on Solarized Light theme"
src="https://github.com/user-attachments/assets/db80fe07-0cea-4a4b-ba14-e6a31f29cfe1"
/>

## Release notes summary

Improve the colors in the default theme for light-theme terminals by
switching from white to default color.


## Tasks after submitting



N/A

crates/nu-color-config/src/shape_color.rs

@@ -18,7 +18,7 @@ pub fn default_shape_color(shape: &str) -> Style {
         "shape_filepath" => Style::new().fg(Color::Cyan),
         "shape_flag" => Style::new().fg(Color::Blue).bold(),
         "shape_float" => Style::new().fg(Color::Purple).bold(),
-        "shape_garbage" => Style::new().fg(Color::White).on(Color::Red).bold(),
+        "shape_garbage" => Style::new().fg(Color::Default).on(Color::Red).bold(),
         "shape_glob_interpolation" => Style::new().fg(Color::Cyan).bold(),
         "shape_globpattern" => Style::new().fg(Color::Cyan).bold(),
         "shape_int" => Style::new().fg(Color::Purple).bold(),

crates/nu-color-config/src/style_computer.rs

@@ -113,27 +113,27 @@ impl<'a> StyleComputer<'a> {
         // Create the hashmap
         #[rustfmt::skip]
         let mut map: StyleMapping = [
-            ("separator".to_string(), ComputableStyle::Static(Color::White.normal())),
+            ("separator".to_string(), ComputableStyle::Static(Color::Default.normal())),
             ("leading_trailing_space_bg".to_string(), ComputableStyle::Static(Style::default().on(Color::Rgb(128, 128, 128)))),
             ("header".to_string(), ComputableStyle::Static(Color::Green.bold())),
             ("empty".to_string(), ComputableStyle::Static(Color::Blue.normal())),
             ("bool".to_string(), ComputableStyle::Static(Color::LightCyan.normal())),
-            ("int".to_string(), ComputableStyle::Static(Color::White.normal())),
+            ("int".to_string(), ComputableStyle::Static(Color::Default.normal())),
             ("filesize".to_string(), ComputableStyle::Static(Color::Cyan.normal())),
-            ("duration".to_string(), ComputableStyle::Static(Color::White.normal())),
+            ("duration".to_string(), ComputableStyle::Static(Color::Default.normal())),
             ("datetime".to_string(), ComputableStyle::Static(Color::Purple.normal())),
-            ("range".to_string(), ComputableStyle::Static(Color::White.normal())),
-            ("float".to_string(), ComputableStyle::Static(Color::White.normal())),
-            ("string".to_string(), ComputableStyle::Static(Color::White.normal())),
-            ("nothing".to_string(), ComputableStyle::Static(Color::White.normal())),
-            ("binary".to_string(), ComputableStyle::Static(Color::White.normal())),
-            ("cell-path".to_string(), ComputableStyle::Static(Color::White.normal())),
+            ("range".to_string(), ComputableStyle::Static(Color::Default.normal())),
+            ("float".to_string(), ComputableStyle::Static(Color::Default.normal())),
+            ("string".to_string(), ComputableStyle::Static(Color::Default.normal())),
+            ("nothing".to_string(), ComputableStyle::Static(Color::Default.normal())),
+            ("binary".to_string(), ComputableStyle::Static(Color::Default.normal())),
+            ("cell-path".to_string(), ComputableStyle::Static(Color::Default.normal())),
             ("row_index".to_string(), ComputableStyle::Static(Color::Green.bold())),
-            ("record".to_string(), ComputableStyle::Static(Color::White.normal())),
-            ("list".to_string(), ComputableStyle::Static(Color::White.normal())),
-            ("block".to_string(), ComputableStyle::Static(Color::White.normal())),
+            ("record".to_string(), ComputableStyle::Static(Color::Default.normal())),
+            ("list".to_string(), ComputableStyle::Static(Color::Default.normal())),
+            ("block".to_string(), ComputableStyle::Static(Color::Default.normal())),
             ("hints".to_string(), ComputableStyle::Static(Color::DarkGray.normal())),
-            ("search_result".to_string(), ComputableStyle::Static(Color::White.normal().on(Color::Red))),
+            ("search_result".to_string(), ComputableStyle::Static(Color::Default.normal().on(Color::Red))),
         ].into_iter().collect();
 
         for (key, value) in &config.color_config {

crates/nu-command/src/filters/find.rs

@@ -75,7 +75,7 @@ impl Command for Find {
                 description: "Search and highlight text for a term in a string.",
                 example: r#"'Cargo.toml' | find Cargo"#,
                 result: Some(Value::test_string(
-                    "\u{1b}[37m\u{1b}[0m\u{1b}[41;37mCargo\u{1b}[0m\u{1b}[37m.toml\u{1b}[0m"
+                    "\u{1b}[39m\u{1b}[0m\u{1b}[41;39mCargo\u{1b}[0m\u{1b}[39m.toml\u{1b}[0m"
                         .to_owned(),
                 )),
             },
@@ -93,10 +93,10 @@ impl Command for Find {
                 result: Some(Value::list(
                     vec![
                         Value::test_string(
-                            "\u{1b}[37m\u{1b}[0m\u{1b}[41;37ml\u{1b}[0m\u{1b}[37marry\u{1b}[0m",
+                            "\u{1b}[39m\u{1b}[0m\u{1b}[41;39ml\u{1b}[0m\u{1b}[39marry\u{1b}[0m",
                         ),
                         Value::test_string(
-                            "\u{1b}[37mcur\u{1b}[0m\u{1b}[41;37ml\u{1b}[0m\u{1b}[37my\u{1b}[0m",
+                            "\u{1b}[39mcur\u{1b}[0m\u{1b}[41;39ml\u{1b}[0m\u{1b}[39my\u{1b}[0m",
                         ),
                     ],
                     Span::test_data(),
@@ -108,11 +108,11 @@ impl Command for Find {
                 result: Some(Value::list(
                     vec![
                         Value::test_string(
-                            "\u{1b}[37ma\u{1b}[0m\u{1b}[41;37mbc\u{1b}[0m\u{1b}[37m\u{1b}[0m"
+                            "\u{1b}[39ma\u{1b}[0m\u{1b}[41;39mbc\u{1b}[0m\u{1b}[39m\u{1b}[0m"
                                 .to_string(),
                         ),
                         Value::test_string(
-                            "\u{1b}[37ma\u{1b}[0m\u{1b}[41;37mbf\u{1b}[0m\u{1b}[37m\u{1b}[0m"
+                            "\u{1b}[39ma\u{1b}[0m\u{1b}[41;39mbf\u{1b}[0m\u{1b}[39m\u{1b}[0m"
                                 .to_string(),
                         ),
                     ],
@@ -125,11 +125,11 @@ impl Command for Find {
                 result: Some(Value::list(
                     vec![
                         Value::test_string(
-                            "\u{1b}[37m\u{1b}[0m\u{1b}[41;37maB\u{1b}[0m\u{1b}[37mc\u{1b}[0m"
+                            "\u{1b}[39m\u{1b}[0m\u{1b}[41;39maB\u{1b}[0m\u{1b}[39mc\u{1b}[0m"
                                 .to_string(),
                         ),
                         Value::test_string(
-                            "\u{1b}[37m\u{1b}[0m\u{1b}[41;37mab\u{1b}[0m\u{1b}[37mf\u{1b}[0m"
+                            "\u{1b}[39m\u{1b}[0m\u{1b}[41;39mab\u{1b}[0m\u{1b}[39mf\u{1b}[0m"
                                 .to_string(),
                         ),
                     ],
@@ -141,7 +141,7 @@ impl Command for Find {
                 example: r#"[[version name]; ['0.1.0' nushell] ['0.1.1' fish] ['0.2.0' zsh]] | find --regex "nu""#,
                 result: Some(Value::test_list(vec![Value::test_record(record! {
                         "version" => Value::test_string("0.1.0"),
-                        "name" => Value::test_string("\u{1b}[37m\u{1b}[0m\u{1b}[41;37mnu\u{1b}[0m\u{1b}[37mshell\u{1b}[0m".to_string()),
+                        "name" => Value::test_string("\u{1b}[39m\u{1b}[0m\u{1b}[41;39mnu\u{1b}[0m\u{1b}[39mshell\u{1b}[0m".to_string()),
                 })])),
             },
             Example {
@@ -165,7 +165,7 @@ impl Command for Find {
                     vec![Value::list(
                         vec![
                             Value::test_string(
-                                "\u{1b}[37mLa\u{1b}[0m\u{1b}[41;37mrr\u{1b}[0m\u{1b}[37my\u{1b}[0m",
+                                "\u{1b}[39mLa\u{1b}[0m\u{1b}[41;39mrr\u{1b}[0m\u{1b}[39my\u{1b}[0m",
                             ),
                             Value::test_string("Moe"),
                         ],
@@ -202,7 +202,7 @@ impl Command for Find {
                 result: Some(Value::list(
                     vec![Value::test_record(record! {
                             "col1" => Value::test_string(
-                                "\u{1b}[37m\u{1b}[0m\u{1b}[41;37mmoe\u{1b}[0m\u{1b}[37m\u{1b}[0m"
+                                "\u{1b}[39m\u{1b}[0m\u{1b}[41;39mmoe\u{1b}[0m\u{1b}[39m\u{1b}[0m"
                                     .to_string(),
                             ),
                             "col2" => Value::test_string("larry".to_string()),
@@ -217,10 +217,10 @@ impl Command for Find {
                 result: Some(Value::list(
                     vec![
                         Value::test_string(
-                            "\u{1b}[37mAnd roses are bl\u{1b}[0m\u{1b}[41;37mue\u{1b}[0m\u{1b}[37m\u{1b}[0m",
+                            "\u{1b}[39mAnd roses are bl\u{1b}[0m\u{1b}[41;39mue\u{1b}[0m\u{1b}[39m\u{1b}[0m",
                         ),
                         Value::test_string(
-                            "\u{1b}[37mAlter their h\u{1b}[0m\u{1b}[41;37mue\u{1b}[0m\u{1b}[37m\u{1b}[0m",
+                            "\u{1b}[39mAlter their h\u{1b}[0m\u{1b}[41;39mue\u{1b}[0m\u{1b}[39m\u{1b}[0m",
                         ),
                     ],
                     Span::test_data(),
@@ -230,7 +230,7 @@ impl Command for Find {
                 description: "Find in a multi-line string without splitting the input into a list of lines",
                 example: r#""Violets are red\nAnd roses are blue\nWhen metamaterials\nAlter their hue" | find --multiline "ue""#,
                 result: Some(Value::test_string(
-                    "\u{1b}[37mViolets are red\nAnd roses are bl\u{1b}[0m\u{1b}[41;37mue\u{1b}[0m\u{1b}[37m\nWhen metamaterials\nAlter their h\u{1b}[0m\u{1b}[41;37mue\u{1b}[0m\u{1b}[37m\u{1b}[0m",
+                    "\u{1b}[39mViolets are red\nAnd roses are bl\u{1b}[0m\u{1b}[41;39mue\u{1b}[0m\u{1b}[39m\nWhen metamaterials\nAlter their h\u{1b}[0m\u{1b}[41;39mue\u{1b}[0m\u{1b}[39m\u{1b}[0m",
                 )),
             },
         ]

crates/nu-command/tests/commands/find.rs

@@ -7,7 +7,7 @@ fn find_with_list_search_with_string() {
 
     assert_eq!(
         actual.out,
-        "\u{1b}[37m\u{1b}[0m\u{1b}[41;37mmoe\u{1b}[0m\u{1b}[37m\u{1b}[0m"
+        "\u{1b}[39m\u{1b}[0m\u{1b}[41;39mmoe\u{1b}[0m\u{1b}[39m\u{1b}[0m"
     );
     assert_eq!(actual_no_highlight.out, "moe");
 }
@@ -19,7 +19,7 @@ fn find_with_list_search_with_char() {
 
     assert_eq!(
         actual.out,
-        "[\"\\u001b[37m\\u001b[0m\\u001b[41;37ml\\u001b[0m\\u001b[37marry\\u001b[0m\",\"\\u001b[37mcur\\u001b[0m\\u001b[41;37ml\\u001b[0m\\u001b[37my\\u001b[0m\"]"
+        "[\"\\u001b[39m\\u001b[0m\\u001b[41;39ml\\u001b[0m\\u001b[39marry\\u001b[0m\",\"\\u001b[39mcur\\u001b[0m\\u001b[41;39ml\\u001b[0m\\u001b[39my\\u001b[0m\"]"
     );
     assert_eq!(actual_no_highlight.out, "[\"larry\",\"curly\"]");
 }
@@ -35,7 +35,7 @@ fn find_with_bytestream_search_with_char() {
 
     assert_eq!(
         actual.out,
-        "\u{1b}[37m\u{1b}[0m\u{1b}[41;37mABC\u{1b}[0m\u{1b}[37m\u{1b}[0m"
+        "\u{1b}[39m\u{1b}[0m\u{1b}[41;39mABC\u{1b}[0m\u{1b}[39m\u{1b}[0m"
     );
     assert_eq!(actual_no_highlight.out, "ABC");
 }
@@ -56,7 +56,7 @@ fn find_with_string_search_with_string() {
 
     assert_eq!(
         actual.out,
-        "\u{1b}[37mCargo.\u{1b}[0m\u{1b}[41;37mtoml\u{1b}[0m\u{1b}[37m\u{1b}[0m"
+        "\u{1b}[39mCargo.\u{1b}[0m\u{1b}[41;39mtoml\u{1b}[0m\u{1b}[39m\u{1b}[0m"
     );
     assert_eq!(actual_no_highlight.out, "Cargo.toml");
 }
@@ -80,7 +80,7 @@ fn find_with_filepath_search_with_string() {
 
     assert_eq!(
         actual.out,
-        "[\"\\u001b[37m\\u001b[0m\\u001b[41;37marep\\u001b[0m\\u001b[37mas.clu\\u001b[0m\"]"
+        "[\"\\u001b[39m\\u001b[0m\\u001b[41;39marep\\u001b[0m\\u001b[39mas.clu\\u001b[0m\"]"
     );
     assert_eq!(actual_no_highlight.out, "[\"arepas.clu\"]");
 }
@@ -95,7 +95,7 @@ fn find_with_filepath_search_with_multiple_patterns() {
 
     assert_eq!(
         actual.out,
-        "[\"\\u001b[37m\\u001b[0m\\u001b[41;37mami\\u001b[0m\\u001b[37mgos.txt\\u001b[0m\",\"\\u001b[37m\\u001b[0m\\u001b[41;37marep\\u001b[0m\\u001b[37mas.clu\\u001b[0m\"]"
+        "[\"\\u001b[39m\\u001b[0m\\u001b[41;39mami\\u001b[0m\\u001b[39mgos.txt\\u001b[0m\",\"\\u001b[39m\\u001b[0m\\u001b[41;39marep\\u001b[0m\\u001b[39mas.clu\\u001b[0m\"]"
     );
     assert_eq!(actual_no_highlight.out, "[\"amigos.txt\",\"arepas.clu\"]");
 }
@@ -121,7 +121,7 @@ fn find_with_regex_in_table_keeps_row_if_one_column_matches() {
 
     assert_eq!(
         actual.out,
-        r#"["\u001b[37mMauri\u001b[0m\u001b[41;37mce\u001b[0m\u001b[37m\u001b[0m","\u001b[37mLauren\u001b[0m\u001b[41;37mce\u001b[0m\u001b[37m\u001b[0m"]"#
+        r#"["\u001b[39mMauri\u001b[0m\u001b[41;39mce\u001b[0m\u001b[39m\u001b[0m","\u001b[39mLauren\u001b[0m\u001b[41;39mce\u001b[0m\u001b[39m\u001b[0m"]"#
     );
     assert_eq!(actual_no_highlight.out, r#"["Maurice","Laurence"]"#);
 }
@@ -225,7 +225,7 @@ fn find_with_string_search_with_special_char_1() {
 
     assert_eq!(
         actual.out,
-        "[{\"d\":\"\\u001b[37ma\\u001b[0m\\u001b[41;37m?\\u001b[0m\\u001b[37mb\\u001b[0m\"}]"
+        "[{\"d\":\"\\u001b[39ma\\u001b[0m\\u001b[41;39m?\\u001b[0m\\u001b[39mb\\u001b[0m\"}]"
     );
     assert_eq!(actual_no_highlight.out, "[{\"d\":\"a?b\"}]");
 }
@@ -238,7 +238,7 @@ fn find_with_string_search_with_special_char_2() {
 
     assert_eq!(
         actual.out,
-        "[{\"d\":\"\\u001b[37ma\\u001b[0m\\u001b[41;37m*\\u001b[0m\\u001b[37mb\\u001b[0m\"}]"
+        "[{\"d\":\"\\u001b[39ma\\u001b[0m\\u001b[41;39m*\\u001b[0m\\u001b[39mb\\u001b[0m\"}]"
     );
     assert_eq!(actual_no_highlight.out, "[{\"d\":\"a*b\"}]");
 }
@@ -251,7 +251,7 @@ fn find_with_string_search_with_special_char_3() {
 
     assert_eq!(
         actual.out,
-        "[{\"d\":\"\\u001b[37ma\\u001b[0m\\u001b[41;37m{1}\\u001b[0m\\u001b[37mb\\u001b[0m\"}]"
+        "[{\"d\":\"\\u001b[39ma\\u001b[0m\\u001b[41;39m{1}\\u001b[0m\\u001b[39mb\\u001b[0m\"}]"
     );
     assert_eq!(actual_no_highlight.out, "[{\"d\":\"a{1}b\"}]");
 }
@@ -264,7 +264,7 @@ fn find_with_string_search_with_special_char_4() {
 
     assert_eq!(
         actual.out,
-        "[{\"d\":\"\\u001b[37ma\\u001b[0m\\u001b[41;37m[\\u001b[0m\\u001b[37m]b\\u001b[0m\"}]"
+        "[{\"d\":\"\\u001b[39ma\\u001b[0m\\u001b[41;39m[\\u001b[0m\\u001b[39m]b\\u001b[0m\"}]"
     );
     assert_eq!(actual_no_highlight.out, "[{\"d\":\"a[]b\"}]");
 }
@@ -277,7 +277,7 @@ fn find_with_string_search_with_special_char_5() {
 
     assert_eq!(
         actual.out,
-        "[{\"d\":\"\\u001b[37ma[\\u001b[0m\\u001b[41;37m]\\u001b[0m\\u001b[37mb\\u001b[0m\"}]"
+        "[{\"d\":\"\\u001b[39ma[\\u001b[0m\\u001b[41;39m]\\u001b[0m\\u001b[39mb\\u001b[0m\"}]"
     );
     assert_eq!(actual_no_highlight.out, "[{\"d\":\"a[]b\"}]");
 }
@@ -290,7 +290,7 @@ fn find_with_string_search_with_special_char_6() {
 
     assert_eq!(
         actual.out,
-        "[{\"d\":\"\\u001b[37ma\\u001b[0m\\u001b[41;37m[]\\u001b[0m\\u001b[37mb\\u001b[0m\"}]"
+        "[{\"d\":\"\\u001b[39ma\\u001b[0m\\u001b[41;39m[]\\u001b[0m\\u001b[39mb\\u001b[0m\"}]"
     );
     assert_eq!(actual_no_highlight.out, "[{\"d\":\"a[]b\"}]");
 }
@@ -308,6 +308,6 @@ fn find_and_highlight_in_nested_list() {
 
     assert_eq!(
         actual.out,
-        r#"[["\u001b[37m\u001b[0m\u001b[41;37mfoo\u001b[0m\u001b[37m\u001b[0m","bar"],["\u001b[37m\u001b[0m\u001b[41;37mfoo\u001b[0m\u001b[37m\u001b[0m","baz"]]"#
+        r#"[["\u001b[39m\u001b[0m\u001b[41;39mfoo\u001b[0m\u001b[39m\u001b[0m","bar"],["\u001b[39m\u001b[0m\u001b[41;39mfoo\u001b[0m\u001b[39m\u001b[0m","baz"]]"#
     );
 }

crates/nu-std/std/config/mod.nu

@@ -2,7 +2,7 @@
 export def dark-theme [] {
     {
         # color for nushell primitives
-        separator: white
+        separator: default
         leading_trailing_space_bg: { attr: n } # no fg, no bg, attr none effectively turns this off
         header: green_bold
         empty: blue
@@ -10,20 +10,20 @@ export def dark-theme [] {
         # The value (in this case, a bool) is piped into the closure.
         # eg) {|| if $in { 'light_cyan' } else { 'light_gray' } }
         bool: light_cyan
-        int: white
+        int: default
         filesize: cyan
-        duration: white
+        duration: default
         datetime: purple
-        range: white
-        float: white
-        string: white
-        nothing: white
-        binary: white
-        cell-path: white
+        range: default
+        float: default
+        string: default
+        nothing: default
+        binary: default
+        cell-path: default
         row_index: green_bold
-        record: white
-        list: white
-        block: white
+        record: default
+        list: default
+        block: default
         hints: dark_gray
         search_result: { bg: red fg: white }
         shape_binary: purple_bold

crates/nu-utils/src/default_files/default_config.nu

@@ -2,29 +2,29 @@
 #
 # version = "0.106.2"
 $env.config.color_config = {
-    separator: white
+    separator: default
     leading_trailing_space_bg: { attr: n }
     header: green_bold
     empty: blue
     bool: light_cyan
-    int: white
+    int: default
     filesize: cyan
-    duration: white
+    duration: default
     datetime: purple
-    range: white
-    float: white
-    string: white
-    nothing: white
-    binary: white
-    cell-path: white
+    range: default
+    float: default
+    string: default
+    nothing: default
+    binary: default
+    cell-path: default
     row_index: green_bold
-    record: white
-    list: white
+    record: default
+    list: default
     closure: green_bold
     glob:cyan_bold
-    block: white
+    block: default
     hints: dark_gray
-    search_result: { bg: red fg: white }
+    search_result: { bg: red fg: default }
     shape_binary: purple_bold
     shape_block: blue_bold
     shape_bool: light_cyan
@@ -61,7 +61,7 @@ $env.config.color_config = {
     shape_vardecl: purple
     shape_raw_string: light_purple
     shape_garbage: {
-        fg: white
+        fg: default
         bg: red
         attr: b
     }