_content: qa updates play page

- adds dark mode functionality for the community menu
- adds 'overflow: auto;' over 'overflow: scroll;' for play page about modal to prevent ghost scroll bars on certain devices.

Change-Id: I175f21aa06b47bd590010551e8bd3757993bea96
Reviewed-on: https://go-review.googlesource.com/c/website/+/453795
Run-TryBot: Jamal Carvalho <jamal@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
diff --git a/_content/css/styles.css b/_content/css/styles.css
index 3e15d85..fede720 100644
--- a/_content/css/styles.css
+++ b/_content/css/styles.css
@@ -766,6 +766,12 @@
     filter: invert(1);
   }
 }
+[data-theme='dark'] .Header-menuItem a.Header-socialIcon.Header-socialIcon-dark {
+  display: inline-flex;
+}
+[data-theme='dark'] .Header-menuItem a.Header-socialIcon.Header-socialIcon-light {
+  display: none;
+}
 /* End nav */
 .Article {
   color: var(--color-text);
diff --git a/_content/images/logos/social/github-light.svg b/_content/images/logos/social/github-light.svg
new file mode 100644
index 0000000..a08fb05
--- /dev/null
+++ b/_content/images/logos/social/github-light.svg
@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" version="1.2"><defs><image id="a" width="32" height="31" href="data:image/png;base64,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"/></defs><use href="#a" transform="scale(.5)"/></svg>
\ No newline at end of file
diff --git a/_content/menus.yaml b/_content/menus.yaml
index 4d83732..d46afa3 100644
--- a/_content/menus.yaml
+++ b/_content/menus.yaml
@@ -57,7 +57,7 @@
               img: google-groups.svg,
               url: 'https://groups.google.com/g/golang-nuts',
             },
-            {img: github.svg, url: 'https://github.com/golang'},
+            {img: github.svg, darkImg: github-light.svg, url: 'https://github.com/golang',},
             {img: twitter.svg, url: 'https://twitter.com/golang'},
             {img: reddit.svg, url: 'https://www.reddit.com/r/golang/'},
             {img: slack.svg, url: 'https://invite.slack.golangbridge.org/'},
diff --git a/_content/site.tmpl b/_content/site.tmpl
index 24c5165..df0fc20 100644
--- a/_content/site.tmpl
+++ b/_content/site.tmpl
@@ -83,7 +83,12 @@
                     {{- if .socialIconsList}}
                       <div class="Header-socialIcons">
                         {{ range .socialIconsList }}
-                          <a class="Header-socialIcon" href="{{.url}}"><img src="/images/logos/social/{{.img}}" /></a>
+                        {{ if .darkImg }}
+                        <a class="Header-socialIcon Header-socialIcon-light" href="{{.url}}"><img src="/images/logos/social/{{.img}}" /></a>
+                        <a class="Header-socialIcon Header-socialIcon-dark" href="{{.url}}"><img src="/images/logos/social/{{.darkImg}}" /></a>
+                        {{else}}
+                        <a class="Header-socialIcon" href="{{.url}}"><img src="/images/logos/social/{{.img}}" /></a>
+                        {{end}}
                         {{- end}}
                       </div>
                     {{- end}}