[FIX] Fix giscus dark mode in new page (PKUFlyingPig#371)

Author: mancuoj

overrides/main.html

@@ -3,11 +3,19 @@
 {% block disqus %}
 <script src="https://giscus.app/client.js" data-repo="PKUFlyingPig/cs-self-learning" data-repo-id="R_kgDOGP67ng"
     data-category="Announcements" data-category-id="DIC_kwDOGP67ns4COM9Q" data-mapping="title"
-    data-reactions-enabled="1" data-emit-metadata="0" data-input-position="top" data-theme="light" data-lang="zh-CN"
-    data-loading="lazy" crossorigin="anonymous" async>
+    data-reactions-enabled="1" data-emit-metadata="0" data-input-position="top" data-theme="light_protanopia"
+    data-lang="zh-CN" data-loading="lazy" crossorigin="anonymous" async>
 </script>
 
 <script>
+    var palette = __get("__palette")
+    if (palette && typeof palette.color === "object") {
+        if (palette.color.scheme === "slate") {
+            const giscus = document.querySelector("script[src*=giscus]")
+            giscus.setAttribute("data-theme", "dark_protanopia")
+        }
+    }
+
     document.addEventListener("DOMContentLoaded", function () {
         const ref = document.querySelector("[data-md-component=palette]")
         ref.addEventListener("change", function () {