修复 真机浏览器端 Banner 图片没有铺满容器的问题

components/HomeBanner.tsx

@@ -170,15 +170,16 @@ export default function HomeBanner() {
         }`}
         aria-label="Home banner"
       >
+        {/* 背景图层 - 完全铺满 */}
         {backgroundImage ? (
-          <img
-            data-alt="background-image"
-            src={backgroundImage}
-            className="absolute inset-0 h-full w-full object-cover"
-          />
-        ) : null}
-        {backgroundImage ? (
-          <div data-alt="background-overlay" className="absolute inset-0 bg-black/40" />
+          <div data-alt="background-wrapper" className="absolute inset-0">
+            <img
+              data-alt="background-image"
+              src={backgroundImage}
+              className="h-full w-full object-cover block"
+            />
+            <div data-alt="background-overlay" className="absolute inset-0 bg-black/40" />
+          </div>
         ) : null}
 
         <div