diff --git a/_extensions/quartoorg/assets/scripts/page-tweaks.html b/_extensions/quartoorg/assets/scripts/page-tweaks.html
index 58075c0d06..f899f04e54 100644
--- a/_extensions/quartoorg/assets/scripts/page-tweaks.html
+++ b/_extensions/quartoorg/assets/scripts/page-tweaks.html
@@ -1,7 +1,7 @@
 <script type="text/javascript">
 
 // replace cmd keyboard shortcut w/ control on non-Mac platforms
-const kPlatformMac = typeof navigator !== 'undefined' ? /Mac/.test(navigator.platform) : false;
+const kPlatformMac = /Macintosh/.test(navigator.userAgent);
 if (!kPlatformMac) {
    var kbds = document.querySelectorAll("kbd")
    kbds.forEach(function(kbd) {
@@ -12,7 +12,7 @@
 // tweak headings in pymd
 document.querySelectorAll(".pymd span.co").forEach(el => {
    if (!el.innerText.startsWith("#|")) {
-      el.style.fontWeight = 1000;
+      el.classList.add("pymd-comment");
    }
 });
 
diff --git a/_extensions/quartoorg/scss/partials/_announcement.scss b/_extensions/quartoorg/scss/partials/_announcement.scss
new file mode 100644
index 0000000000..853126dc98
--- /dev/null
+++ b/_extensions/quartoorg/scss/partials/_announcement.scss
@@ -0,0 +1,11 @@
+#quarto-announcement {
+  padding: 1em;
+  font-size: 1em;
+  font-weight: bold;
+  color: $white;
+  background-color: #447099;
+}
+
+#quarto-announcement a {
+  color: $white;
+}
diff --git a/_extensions/quartoorg/scss/partials/_content.scss b/_extensions/quartoorg/scss/partials/_content.scss
index 54835f3a9f..de12ee0618 100644
--- a/_extensions/quartoorg/scss/partials/_content.scss
+++ b/_extensions/quartoorg/scss/partials/_content.scss
@@ -70,3 +70,9 @@ table.quarto-listing-table .listing-description a {
 pre.sourceCode.visually-hidden {
   overflow: hidden !important;
 }
+
+/* page-tweaks.html marks the comments in .pymd blocks that are not
+   `#|` cell options. */
+.pymd-comment {
+  font-weight: 1000;
+}
diff --git a/_extensions/quartoorg/scss/partials/_dark-rules.scss b/_extensions/quartoorg/scss/partials/_dark-rules.scss
index b9753c546f..efcdb87a92 100644
--- a/_extensions/quartoorg/scss/partials/_dark-rules.scss
+++ b/_extensions/quartoorg/scss/partials/_dark-rules.scss
@@ -90,18 +90,6 @@ details > summary {
   color: $text-muted;
 }
 
-#quarto-announcement {
-  padding: 1em;
-  font-size: 1em;
-  font-weight: bold;
-  color: $white;
-  background-color: #447099; 
-}
-
-#quarto-announcement a {
-  color: $white;
-}
-
 /*Footer Posit logo color for dark mode*/
 
 img.footer-logo {
diff --git a/_extensions/quartoorg/scss/partials/_light-rules.scss b/_extensions/quartoorg/scss/partials/_light-rules.scss
index 3a16f547b2..96a35da9ff 100644
--- a/_extensions/quartoorg/scss/partials/_light-rules.scss
+++ b/_extensions/quartoorg/scss/partials/_light-rules.scss
@@ -34,15 +34,3 @@
   text-align: right;
   padding-right: 1em;
 }
-
-#quarto-announcement {
-  padding: 1em;
-  font-size: 1em;
-  font-weight: bold;
-  color: $white;
-  background-color: #447099; 
-}
-
-#quarto-announcement a {
-  color: $white;
-}
diff --git a/_extensions/quartoorg/scss/partials/_navbar.scss b/_extensions/quartoorg/scss/partials/_navbar.scss
index 9bac8f1977..c1bb20b533 100644
--- a/_extensions/quartoorg/scss/partials/_navbar.scss
+++ b/_extensions/quartoorg/scss/partials/_navbar.scss
@@ -18,7 +18,6 @@
   margin-left: .1em;
 }
 
-.navbar .bi-twitter,
 .navbar .bi-github,
 .navbar .bi-rss
  {
diff --git a/_extensions/quartoorg/scss/partials/_site.scss b/_extensions/quartoorg/scss/partials/_site.scss
index 2b729fdc25..1b5a547543 100644
--- a/_extensions/quartoorg/scss/partials/_site.scss
+++ b/_extensions/quartoorg/scss/partials/_site.scss
@@ -12,3 +12,4 @@
 @import "figures";
 @import "color-box";
 @import "home";
+@import "announcement";
diff --git a/_extensions/quartoorg/scss/prerelease-banner.scss b/_extensions/quartoorg/scss/prerelease-banner.scss
index ffc40d3e1e..d633629b19 100644
--- a/_extensions/quartoorg/scss/prerelease-banner.scss
+++ b/_extensions/quartoorg/scss/prerelease-banner.scss
@@ -4,8 +4,5 @@
 // #e60033 gives white text 4.76:1 (WCAG 1.4.3 needs 4.5:1).
 // Cosmo's $danger (#ff0039) gives only 3.95:1.
 #quarto-announcement {
-  font-size: 1em;
-  font-weight: bold;
-  color: $white;
   background-color: #e60033;
 }
diff --git a/images/demo-jupyter.png b/images/demo-jupyter.png
deleted file mode 100644
index b733fd5b0a..0000000000
Binary files a/images/demo-jupyter.png and /dev/null differ
diff --git a/images/hello-julia.bak2.png b/images/hello-julia.bak2.png
deleted file mode 100644
index 4d73da03d1..0000000000
Binary files a/images/hello-julia.bak2.png and /dev/null differ
diff --git a/images/hello-jupyter-notebook.png b/images/hello-jupyter-notebook.png
deleted file mode 100644
index c41b0f78f9..0000000000
Binary files a/images/hello-jupyter-notebook.png and /dev/null differ
diff --git a/images/hello-jupyter.bak.png b/images/hello-jupyter.bak.png
deleted file mode 100644
index 538e92f5b4..0000000000
Binary files a/images/hello-jupyter.bak.png and /dev/null differ