fix(colors): Correct perceptual correction threshold

Changed threshold from 0.45 to 0.15 so that:
- Blue (~0.07 luminance) gets boost to avoid "goes to black" effect
- Red (~0.21 luminance) is NOT affected (already darkens nicely)

This fixes the issue where red panels became too saturated.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/core/style.zig

@@ -42,9 +42,10 @@ pub fn isFancy() bool {
 // =============================================================================
 
 /// Enable perceptual correction for panel colors.
-/// NOTE: Desactivado por defecto - la lógica actual boostea el rojo cuando
+/// When enabled, colors with VERY low perceived luminance (e.g., blue ~0.07)
-/// debería compensar el azul. Requiere revisión del algoritmo.
+/// get a boost to avoid going to black when darkened.
-var perceptual_correction_enabled: bool = false;
+/// Colors like red (~0.21) are NOT affected as they darken well naturally.
+var perceptual_correction_enabled: bool = true;
 
 /// Get whether perceptual correction is enabled
 pub fn isPerceptualCorrectionEnabled() bool {
@@ -1076,15 +1077,15 @@ fn deriveDarkPalette(base: Color) PanelColorScheme {
     const gray = Color.rgb(128, 128, 128);
     const dark_border = Color.rgb(60, 60, 65);
 
-    // Perceptual correction: boost low-luminance colors to match visual contrast
+    // Perceptual correction: only for colors with VERY low luminance (like pure blue ~0.07)
-    // Reference: laravel_blue has luminance ~0.48, we use 0.45 as target
+    // Red (~0.21) is above threshold and won't be affected
     const base_lum = base.perceptualLuminance();
-    const target_lum: f32 = 0.45; // Reference luminance (approximately blue)
+    const threshold: f32 = 0.15; // Only affect colors below this (blue=0.07, red=0.21)
 
-    // Calculate correction factor: if luminance is lower than target, reduce blend %
+    // Calculate correction factor: if luminance is VERY low, reduce blend %
-    // This makes more of the base color visible, compensating for lower brightness
+    // This makes more of the base color visible, preventing "goes to black" effect
-    const correction: f32 = if (perceptual_correction_enabled and base_lum < target_lum)
+    const correction: f32 = if (perceptual_correction_enabled and base_lum < threshold)
-        @max(0.7, base_lum / target_lum) // Cap at 0.7 to avoid excessive boost
+        @max(0.75, base_lum / threshold) // Subtle boost for very dark colors
     else
         1.0;
 
@@ -1130,13 +1131,13 @@ fn deriveLightPalette(base: Color) PanelColorScheme {
     const gray = Color.rgb(128, 128, 128);
     const light_border = Color.rgb(220, 220, 225);
 
-    // Perceptual correction: boost low-luminance colors to match visual contrast
+    // Perceptual correction: only for colors with VERY low luminance (like pure blue ~0.07)
-    // In light mode, lower blend % means more base color visible
+    // Red (~0.21) is above threshold and won't be affected
     const base_lum = base.perceptualLuminance();
-    const target_lum: f32 = 0.45;
+    const threshold: f32 = 0.15; // Only affect colors below this (blue=0.07, red=0.21)
 
-    const correction: f32 = if (perceptual_correction_enabled and base_lum < target_lum)
+    const correction: f32 = if (perceptual_correction_enabled and base_lum < threshold)
-        @max(0.7, base_lum / target_lum)
+        @max(0.75, base_lum / threshold) // Subtle boost for very dark colors
     else
         1.0;