确保 no-login 容器始终可见

- 添加 visibility: visible !important 保证可见性
- display: flex !important 确保显示

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

css/index.css

@@ -135,6 +135,7 @@
   margin: 0 !important;
   padding: 0 !important;
   flex-direction: row !important;
+  visibility: visible !important;
 }
 
 /* 注册按钮 - 渐变背景样式，撑满高度 */