style: 使用次级背景色变量替换硬编码白色背景

将PointsCollector和TotalPointsDisplay组件的白色背景替换为定义的--secondary-color-bg变量，保持UI样式一致性并在app.less中新增该变量定义

@@ -12,6 +12,7 @@
   --color-primary: var(--primary-color);
   --color-primary: var(--primary-color);
   --color-text: #9CA3AF;
   --color-text: #9CA3AF;
   --primary-color-rgb: 84, 171, 174;
   --primary-color-rgb: 84, 171, 174;
+  --secondary-color-bg: #E7E7E7;
 }
 }
 
 
 .bg-blue-500 {
 .bg-blue-500 {

@@ -437,7 +437,7 @@ const handleGoToRewards = () => {
 
 
 <style lang="less">
 <style lang="less">
 .points-collector-container {
 .points-collector-container {
-  background: white;
+  background: var(--secondary-color-bg);
   border-radius: 24rpx;
   border-radius: 24rpx;
   box-shadow: 0 4rpx 20rpx rgba(0, 0, 0, 0.08);
   box-shadow: 0 4rpx 20rpx rgba(0, 0, 0, 0.08);
   margin: 32rpx;
   margin: 32rpx;

@@ -129,7 +129,7 @@ const handleGoToPointsRule = () => {
 
 
 <style lang="less">
 <style lang="less">
 .total-points-display-container {
 .total-points-display-container {
-  background: white;
+  background: var(--secondary-color-bg);
   border-radius: 24rpx;
   border-radius: 24rpx;
   box-shadow: 0 4rpx 20rpx rgba(0, 0, 0, 0.08);
   box-shadow: 0 4rpx 20rpx rgba(0, 0, 0, 0.08);
   margin: 32rpx;
   margin: 32rpx;