diff --git a/convert-w2p.js b/convert-w2p.js
index a3fae21..644b3be 100644
--- a/convert-w2p.js
+++ b/convert-w2p.js
@@ -521,7 +521,12 @@ async function convert(input) {
         if (hex) slideBg = { color: hex };
       }
     }
-    // fallback：从 slide 容器的文字颜色反推背景
+    // fallback：canvas 背景色（实际页面背景色）
+    if (!slideBg && canvas.backgroundColor && canvas.backgroundColor !== 'rgba(0, 0, 0, 0)') {
+      const canvasHex = rgbaToHex(canvas.backgroundColor);
+      if (canvasHex) slideBg = { color: canvasHex };
+    }
+    // fallback：从文字颜色推断
     if (!slideBg && slideContainer && slideContainer.styles) {
       const textColor = slideContainer.styles.color;
       if (textColor) {
@@ -531,21 +536,10 @@ async function convert(input) {
           const g = parseInt(tc.slice(2,4), 16);
           const b = parseInt(tc.slice(4,6), 16);
           const lum = (r * 299 + g * 587 + b * 114) / 1000;
-          // 浅色文字 → 深色背景（用 canvas 背景色），深色文字 → 浅色背景（取反）
-          if (lum > 128) {
-            const canvasBg = canvas.backgroundColor ? rgbaToHex(canvas.backgroundColor) : null;
-            slideBg = { color: canvasBg || '1A1A1A' };
-          } else {
-            slideBg = { color: 'FAFAFA' };
-          }
+          slideBg = lum > 128 ? { color: '1A1A1A' } : { color: 'FAFAFA' };
         }
       }
     }
-    // fallback：从 canvas 背景色兜底（最后手段）
-    if (!slideBg && canvas.backgroundColor && canvas.backgroundColor !== 'rgba(0, 0, 0, 0)') {
-      const hex = rgbaToHex(canvas.backgroundColor);
-      if (hex) slideBg = { color: hex };
-    }
     
     console.log('处理 ' + sg.name + ': ' + sg.children.length + ' 个节点');
 
diff --git a/web-to-ppt/convert-browser.js b/web-to-ppt/convert-browser.js
index 479536a..1864806 100644
--- a/web-to-ppt/convert-browser.js
+++ b/web-to-ppt/convert-browser.js
@@ -220,6 +220,12 @@ async function convertToPptx(input, onProgress) {
         if (hex) slideBg = { color: hex };
       }
     }
+    // fallback：canvas 背景色（实际页面背景色）
+    if (!slideBg && canvas.backgroundColor && canvas.backgroundColor !== 'rgba(0, 0, 0, 0)') {
+      const canvasHex = rgbaToHex(canvas.backgroundColor);
+      if (canvasHex) slideBg = { color: canvasHex };
+    }
+    // fallback：从文字颜色推断
     if (!slideBg && slideNode?.styles) {
       const textColor = slideNode.styles.color;
       if (textColor) {
@@ -229,12 +235,7 @@ async function convertToPptx(input, onProgress) {
           const g = parseInt(tc.slice(2,4), 16);
           const b = parseInt(tc.slice(4,6), 16);
           const lum = (r * 299 + g * 587 + b * 114) / 1000;
-          if (lum > 128) {
-            const canvasBg = canvas.backgroundColor ? rgbaToHex(canvas.backgroundColor) : null;
-            slideBg = { color: canvasBg || '1A1A1A' };
-          } else {
-            slideBg = { color: 'FAFAFA' };
-          }
+          slideBg = lum > 128 ? { color: '1A1A1A' } : { color: 'FAFAFA' };
         }
       }
     }