[Feature] 夜间模式/深色背景

[YocyCraft]

What new features do you want? - 你想要什么新功能？

在配置中允许玩家将教程书的背景图与GUI颜色调整为深色，文字颜色调整为浅色。

This issue is unique - 这个issue是唯一的

• I have searched the issue tracker and confirmed that there is no identical issue. 我已经搜索问题追踪器并且确认没有相同的 Issue。
• I admit that I previously checked all options without thorough verification and directly submitted this Issue, and I agree that it can be closed directly. 我承认此前未充分核实便勾选了所有选项并直接提交此 Issue ，且同意该 Issue 可被直接关闭。
• I confirm that I am currently using the latest snapshot or LTS version of the mod. If not, this issue can be closed directly. 我确认当前使用的是模组的最新快照版本或 LTS 版本，若非如此，此 Issue 可被直接关闭。
• I promise to provide a detailed description of the new feature I want, along with reasonable justification, rather than offering incomplete or vague information. 我承诺我会详细描述我想要的新功能，并附上合理的理由，而非提供不完整或模糊的信息。