Auto merge of rust-lang#12350 - hamirmahal:style/sync-GitHub-Corner-colors, r=xFrednet

style: sync GitHub Corner colors

fixes rust-lang#12349.

*Please write a short comment explaining your change (or "none" for internal only changes)*

changelog: sync site GitHub Corner colors

Author: bors

util/gh-pages/index.html

@@ -594,19 +594,9 @@ <h2 class="panel-title">
             ></path>
         </svg>
         <style>
-            :root {
-                --theme-background-color: black;
-                --theme-foreground-color: white;
-            }
-            @media (prefers-color-scheme: dark) {
-                :root {
-                    --theme-background-color: white;
-                    --theme-foreground-color: black;
-                }
-            }
             .github-corner svg {
-                fill: var(--theme-background-color);
-                color: var(--theme-foreground-color);
+                fill: var(--fg);
+                color: var(--bg);
             }
             .github-corner:hover .octo-arm {
                 animation: octocat-wave 560ms ease-in-out;