Add explicit light background to examples containers

[Copilot]

Updates the T8Example.vue component to ensure non-dark theme examples have an explicit white background color for better visual consistency and readability.

Changes Made

• Theme Detection: Added a computed property isDarkTheme that checks if an example should use dark theme based on:
  • mode prop being 'dark'
  • containerClass prop containing 'dark'
• Conditional Styling: Applied a light CSS class to render containers when !isDarkTheme is true
• Light Background: Added .render-container.light CSS rule with background-color: #ffffff

The dark theme examples continue to use the existing dark background (#1a1a1a), while light theme examples now have an explicit white background instead of relying on the default var(--vp-c-bg).

Testing

• ✅ Site builds successfully without errors
• ✅ Verified both English and Chinese examples pages render correctly
• ✅ Confirmed light theme examples display white background (#ffffff)
• ✅ Confirmed dark theme examples maintain dark background (#1a1a1a)
• ✅ Code review completed with no issues
• ✅ CodeQL security check passed with no vulnerabilities

Screenshots

Light theme examples with white background:

Dark theme example maintaining dark background:

Chinese examples page:

The changes are minimal and surgical, affecting only the background color logic without altering the core T8 rendering functionality.

Original prompt

Update the examples page on the official site of the antvis/T8 repository. Specifically, ensure that if the examples are not in dark theme, the background color of the container div is set to a light color. Adjust the necessary code logic to determine if the theme is dark, and add the required styling to implement a light background color accordingly.

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[hustcc]

@copilot 继续

[Copilot]

@copilot 继续

已完成所有任务！✅

实现的功能：

• 为非暗色主题的示例容器添加了明确的白色背景 (#ffffff)
• 通过检测 mode 和 containerClass 属性来判断是否为暗色主题
• 英文和中文示例页面均已验证正常工作

测试结果：

• ✅ 网站构建成功
• ✅ 浅色主题示例显示白色背景
• ✅ 暗色主题示例保持深色背景 (#1a1a1a)
• ✅ 代码审查无问题
• ✅ 安全检查无漏洞

截图：

• 浅色背景示例
• 暗色主题示例
• 中文页面