add a custom theme for Miniflux like Reeder (#83)

miniflux-theme-reeder
仿 Reeder Miniflux v2 的自定义主题

使用css原生嵌套
支持自定义配置
基于官方css修改
移除冗余操作
适配移动端
适配dark暗黑模式
适配Miniflux版本：2.1.1

README.md

@@ -803,6 +803,7 @@ Inspired by [Awesome lists](https://github.com/sindresorhus/awesome) and [@realS
 ### Miniflux
 
 - [reminiflux](https://reminiflux.github.io/) <sup>[858](https://t.me/s/aboutrss/858)</sup> [![Open-Source Software][oss icon]](https://github.com/reminiflux/reminiflux)
+- [miniflux-theme-reeder](https://github.com/rootknight/Miniflux-Theme-Reeder) [![Open-Source Software][oss icon]](https://github.com/rootknight/Miniflux-Theme-Reeder)
 
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