diff --git a/src/generate.ts b/src/generate.ts
index 0ea3d1c..0424406 100644
--- a/src/generate.ts
+++ b/src/generate.ts
@@ -1,4 +1,4 @@
-import type { ColorInput} from '@ant-design/fast-color';
+import type { ColorInput } from '@ant-design/fast-color';
 import { FastColor } from '@ant-design/fast-color';
 
 const hueStep = 2; // 色相阶梯
@@ -79,9 +79,8 @@ function getValue(hsv: HsvObject, i: number, light?: boolean): number {
   } else {
     value = hsv.v - brightnessStep2 * i;
   }
-  if (value > 1) {
-    value = 1;
-  }
+  // Clamp value between 0 and 1
+  value = Math.max(0, Math.min(1, value));
   return Math.round(value * 100) / 100;
 }
 
diff --git a/tests/index.test.ts b/tests/index.test.ts
index d2ee21b..d154970 100644
--- a/tests/index.test.ts
+++ b/tests/index.test.ts
@@ -83,3 +83,9 @@ test('should contain preseted palettes', () => {
   ]);
   expect([...presetPalettes.blue]).toEqual(presetBlueColors);
 });
+
+test('Generate grey colors', () => {
+  // 测试灰色（h=0, s=0 的特殊情况）
+  expect(generate('#666666')).toBeTruthy();
+  expect(generate('#666666', { theme: 'dark' })).toBeTruthy();
+});