feat: 会员中心全局暗色主题重构

阶段一：全局覆盖
- 新增 dark-override.css (450+ 行)，覆盖所有 Element UI 组件暗色样式
  - 输入框、表格、Tabs、弹窗、按钮、分页、复选框、下拉框等
  - 侧边栏、顶栏、主内容区暗色背景
  - 滚动条、日期选择器、消息面板等
- header.php 引入 dark-override.css

阶段二：页面独立 CSS 暗色化（22 个文件）
- 白色背景 #fff → #161b22
- 浅灰背景 #F3F5F9 → #0d1117
- 深色文字 #171725/#1E2736 → #E6E8EB
- 灰色文字 #8692B0 → #8B949E
- 浅色边框 #E6E7EB → rgba(255,255,255,0.06)
- 悬停背景 #F5F7FA → #21262d

clientarea/hgcloud/css/news.css

@@ -10,7 +10,7 @@
 }
 .news .main-card .main-card-title {
   font-size: 0.28rem;
-  color: #171725;
+  color: #E6E8EB;
   margin-bottom: 0.24rem;
 }
 .news .main-card .search-input {
@@ -48,7 +48,7 @@
 }
 .news .tit {
   font-size: 0.2rem;
-  color: #171725;
+  color: #E6E8EB;
   line-height: 1;
 }
 .news .com-search {
@@ -113,7 +113,7 @@
   color: var(--color-danger);
 }
 .news .tag.def {
-  background: #E1F0FF;
+  background: rgba(22,93,255,0.1);
   color: var(--color-info);
 }
 .news .total {
@@ -123,7 +123,7 @@
   align-items: center;
   line-height: 0.2rem;
   font-size: 0.16rem;
-  color: #171725;
+  color: #E6E8EB;
   padding-left: 0.2rem;
   margin-bottom: 0.2rem;
   box-sizing: border-box;
@@ -179,7 +179,7 @@
 .news .news-list .item .item-right {
   width: 100%;
   height: 0.84rem;
-  border-bottom: 1px solid #E6E7EB;
+  border-bottom: 1px solid rgba(255,255,255,0.06);
 }
 .news .news-list .title {
   margin-bottom: 0.1rem;
@@ -195,7 +195,7 @@
 /* news_detail */
 .news_detail .main-card-title {
   padding-bottom: 0.2rem;
-  border-bottom: 1px solid #E6E7EB;
+  border-bottom: 1px solid rgba(255,255,255,0.06);
 }
 .news_detail .back {
   cursor: pointer;
@@ -207,7 +207,7 @@
 }
 .news_detail .news_annex a {
   text-decoration: none;
-  color: #171725;
+  color: #E6E8EB;
 }
 .news_detail .news_annex a:hover {
   text-decoration: underline;
@@ -215,7 +215,7 @@
 }
 .news_detail .new-box {
   width: 10.33rem;
-  border: 1px solid #E6E7EB;
+  border: 1px solid rgba(255,255,255,0.06);
   margin: 0.4rem auto;
   padding: 0.3rem 0.5rem;
   box-sizing: border-box;
@@ -223,7 +223,7 @@
 .news_detail .new-box .tit {
   line-height: 1.2;
   font-size: 0.28rem;
-  color: #171725;
+  color: #E6E8EB;
   margin-bottom: 0.14rem;
 }
 .news_detail .new-box .time {
@@ -257,7 +257,7 @@
 .news_detail .page .link a {
   display: block;
   font-size: 0.14rem;
-  color: #171725;
+  color: #E6E8EB;
   text-decoration: none;
   text-overflow: ellipsis;
   overflow: hidden;