Add a dim text style

A later commit shows the hashes of commits outside the bisect range in a
dimmer variant of the default text color. A darker shade of a terminal
palette color can't be derived, because we don't know what the palette
is, so leave the shading to the terminal and use its faint attribute,
SGR 2. In gookit/color that attribute is called OpFuzzy.

Terminals that don't implement SGR 2 render the text in its normal color.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

pkg/gui/style/basic_styles.go

@@ -34,6 +34,7 @@ var (
 
 	AttrUnderline = New().SetUnderline()
 	AttrBold      = New().SetBold()
+	AttrDim       = New().SetDim()
 
 	ColorMap = map[string]struct {
 		Foreground TextStyle

pkg/gui/style/decoration.go

@@ -4,6 +4,7 @@ import "github.com/gookit/color"
 
 type Decoration struct {
 	bold          bool
+	dim           bool
 	underline     bool
 	reverse       bool
 	strikethrough bool
@@ -13,6 +14,10 @@ func (d *Decoration) SetBold() {
 	d.bold = true
 }
 
+func (d *Decoration) SetDim() {
+	d.dim = true
+}
+
 func (d *Decoration) SetUnderline() {
 	d.underline = true
 }
@@ -26,12 +31,16 @@ func (d *Decoration) SetStrikethrough() {
 }
 
 func (d Decoration) ToOpts() color.Opts {
-	opts := make([]color.Color, 0, 3)
+	opts := make([]color.Color, 0, 5)
 
 	if d.bold {
 		opts = append(opts, color.OpBold)
 	}
 
+	if d.dim {
+		opts = append(opts, color.OpFuzzy)
+	}
+
 	if d.underline {
 		opts = append(opts, color.OpUnderscore)
 	}
@@ -52,6 +61,10 @@ func (d Decoration) Merge(other Decoration) Decoration {
 		d.bold = true
 	}
 
+	if other.dim {
+		d.dim = true
+	}
+
 	if other.underline {
 		d.underline = true
 	}

pkg/gui/style/style_test.go

@@ -68,6 +68,25 @@ func TestMerge(t *testing.T) {
 			},
 			"\x1b[1mfoo\x1b[0m",
 		},
+		{
+			"dim attribute",
+			[]TextStyle{AttrDim},
+			TextStyle{
+				decoration: Decoration{dim: true},
+				Style:      color.Style{color.OpFuzzy},
+			},
+			"\x1b[2mfoo\x1b[0m",
+		},
+		{
+			"dim attribute and color",
+			[]TextStyle{FgRed.SetDim()},
+			TextStyle{
+				fg:         &Color{basic: &fgRed},
+				decoration: Decoration{dim: true},
+				Style:      color.Style{fgRed, color.OpFuzzy},
+			},
+			"\x1b[31;2mfoo\x1b[0m",
+		},
 		{
 			"multiple attributes",
 			[]TextStyle{AttrBold, AttrUnderline},

pkg/gui/style/text_style.go

@@ -63,6 +63,12 @@ func (b TextStyle) SetBold() TextStyle {
 	return b
 }
 
+func (b TextStyle) SetDim() TextStyle {
+	b.decoration.SetDim()
+	b.Style = b.deriveStyle()
+	return b
+}
+
 func (b TextStyle) SetUnderline() TextStyle {
 	b.decoration.SetUnderline()
 	b.Style = b.deriveStyle()