[优化] 封面背景

app/src/main/java/io/legado/app/ui/widget/components/cover/CoilBookCover.kt

@@ -81,7 +81,11 @@ fun CoilBookCover(
     }
 
     NormalCard(
-        cornerRadius = 4.dp
+        cornerRadius = 4.dp,
+        containerColor = if (!hasCustomDefault && !isOnlineCoverLoaded) {
+            LegadoTheme.colorScheme.surfaceContainerLow
+        } else
+            LegadoTheme.colorScheme.surfaceContainerLow.copy(alpha = 0f)
     ){
         BoxWithConstraints(
             modifier = modifier
@@ -91,11 +95,6 @@ fun CoilBookCover(
                         Modifier.shadow(4.dp, RoundedCornerShape(4.dp))
                     } else Modifier
                 )
-                .then(
-                    if (!hasCustomDefault && !isOnlineCoverLoaded) {
-                        Modifier.background(LegadoTheme.colorScheme.surfaceContainer)
-                    } else Modifier
-                )
         ) {
             val density = LocalDensity.current
             val iconSizeDp = with(density) {