diff --git a/README.md b/README.md
index 7ab059e..92030b8 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@
 [![Platform](https://img.shields.io/badge/platform-Windows%20%7C%20macOS%20%7C%20Linux-111997.svg)](#build--distribution)
 [![Electron](https://img.shields.io/badge/Electron-43-47848F.svg)](https://www.electronjs.org/)
 [![Downloads](https://img.shields.io/github/downloads/CaYatur/SoundVisualizer/total?label=downloads)](https://github.com/CaYatur/SoundVisualizer/releases)
-[![Tests](https://img.shields.io/badge/tests-2547%20passing-2ea043.svg)](#tests)
+[![Tests](https://img.shields.io/badge/tests-2548%20passing-2ea043.svg)](#tests)
 [![cayadev.com](https://img.shields.io/badge/cayadev.com-e11d2a.svg)](https://cayadev.com)
 
 </div>
@@ -1341,7 +1341,7 @@ npm test
 npm start -- --smoke
 ```
 
-**2547 unit tests, all passing.** They are written to check answers, not to exercise lines:
+**2548 unit tests, all passing.** They are written to check answers, not to exercise lines:
 
 - **Formulas** are checked against values derived by hand from their definitions — Viviani's curve
   staying on its sphere, the torus tube radius, Chladni's m↔n antisymmetry, every attractor
diff --git a/README.tr.md b/README.tr.md
index 2f6297d..b16f433 100644
--- a/README.tr.md
+++ b/README.tr.md
@@ -12,7 +12,7 @@
 [![Platform](https://img.shields.io/badge/platform-Windows%20%7C%20macOS%20%7C%20Linux-111997.svg)](#paketleme--dağıtım)
 [![Electron](https://img.shields.io/badge/Electron-43-47848F.svg)](https://www.electronjs.org/)
 [![İndirme](https://img.shields.io/github/downloads/CaYatur/SoundVisualizer/total?label=indirme)](https://github.com/CaYatur/SoundVisualizer/releases)
-[![Test](https://img.shields.io/badge/test-2547%20geçiyor-2ea043.svg)](#testler)
+[![Test](https://img.shields.io/badge/test-2548%20geçiyor-2ea043.svg)](#testler)
 [![cayadev.com](https://img.shields.io/badge/cayadev.com-e11d2a.svg)](https://cayadev.com)
 
 </div>
@@ -1341,7 +1341,7 @@ npm test
 npm start -- --smoke
 ```
 
-**2547 birim testi, hepsi geçiyor.** Satır çalıştırmak için değil, cevap denetlemek için yazıldılar:
+**2548 birim testi, hepsi geçiyor.** Satır çalıştırmak için değil, cevap denetlemek için yazıldılar:
 
 - **Formüller**, tanımlarından elle türetilmiş değerlerle sınanıyor — Viviani eğrisinin küre
   üzerinde kalması, simidin boru yarıçapı, Chladni'nin m↔n antisimetrisi, her çekicinin sınırlı
diff --git a/ROADMAP.md b/ROADMAP.md
index aebef4e..fef8aad 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -129,7 +129,7 @@ npm test
 npm start -- --smoke
 ```
 
-- **2547 unit tests, all passing** on `main`. 703 of those shipped in v3.1.0;
+- **2548 unit tests, all passing** on `main`. 703 of those shipped in v3.1.0;
   105 came with v3.1.1; 163 came with v3.1.2; 157 came with v3.1.3 — 1128 at
   that tag — 469 more with v3.1.4, most of them from the MilkDrop work, and 878
   on `main` since.
diff --git a/src/shared/defaults.js b/src/shared/defaults.js
index 8ba55fa..e7b55bb 100644
--- a/src/shared/defaults.js
+++ b/src/shared/defaults.js
@@ -229,8 +229,8 @@
     visualizer: {
       // Tüm türler ve grupları: shared/mode-catalog.js (#638)
       type: 'bars',
-      colorMode: 'rainbow', // 'custom' | 'theme' | 'rainbow'
-      rainbow: true,
+      colorMode: 'theme', // 'custom' | 'theme' | 'rainbow'
+      rainbow: false,
       color: '#3aa6ff',
       color2: '#d24bff',
       barCount: 160,
diff --git a/tests/background-color-mode.test.js b/tests/background-color-mode.test.js
index 6378965..f1af9d4 100644
--- a/tests/background-color-mode.test.js
+++ b/tests/background-color-mode.test.js
@@ -25,6 +25,17 @@ test('kaynak: resolveBackgroundColors disa acik', () => {
   assert.match(defaultsSrc, /resolveBackgroundColors,/);
 });
 
+test('factory: visualizer + background colorMode default to theme', () => {
+  const SV = loadSV();
+  const cfg = SV.defaultConfig();
+  assert.strictEqual(cfg.visualizer.colorMode, 'theme');
+  assert.strictEqual(cfg.visualizer.rainbow, false);
+  assert.strictEqual(cfg.background.colorMode, 'theme');
+  /* Source of truth in defaults.js — visualizer must not default to rainbow. */
+  assert.match(defaultsSrc, /visualizer:\s*\{[\s\S]*?colorMode:\s*'theme'/);
+  assert.doesNotMatch(defaultsSrc, /visualizer:\s*\{[\s\S]*?colorMode:\s*'rainbow'/);
+});
+
 test('resolve: theme gradient.colors kullanir', () => {
   const SV = loadSV();
   const cols = ['#111111', '#222222', '#333333', '#444444', '#555555'];