Add the color-scheme meta tag (#523)

* Add the color-scheme meta tag

* Update CONTRIBUTORS.md

CONTRIBUTORS.md

@@ -95,3 +95,4 @@
 - [Alphonse Mariya](https://github.com/alfunx)
 - [Ziwei Pan](https://github.com/PanZiwei/)
 - [Viktar Patotski](https://github.com/xp-vit)
+- [cuso4-5h2o](https://www.cuso4.me)

layouts/_default/baseof.html

@@ -5,6 +5,8 @@
     <meta charset="utf-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <meta http-equiv="Content-Language" content="{{ .Site.Language.Lang }}">
+    <meta name="color-scheme" content="light dark">
+    
     {{ if .Site.Params.csp }}
       {{ partial "csp.html" . }}
     {{ end }}