暗色模式上线啦！！

馋好久了，最近总算是改完了

当切换系统的色彩方案（亮/暗）时，能自动切换到对应的模式

相关提交

• https://github.com/jiangtj/hexo-theme-cake/pull/55
• https://github.com/jiangtj-lab/hexo-cake-local-search/commit/350e77722eca991e9678abdd8278663eda66d1dc
• https://github.com/jiangtj-lab/hexo-cake-moon-menu/commit/8556fe6cb26e993c99805cd9b9d28d80039734b1