diff --git a/inst/reveal.js-5.2.1/css/theme/source/ids.scss b/inst/reveal.js-5.2.1/css/theme/source/ids.scss
index 9791304..7144eeb 100644
--- a/inst/reveal.js-5.2.1/css/theme/source/ids.scss
+++ b/inst/reveal.js-5.2.1/css/theme/source/ids.scss
@@ -19,6 +19,10 @@
 // decks get it from too); the others are kept for locally installed copies.
 @import url('https://fonts.googleapis.com/css2?family=Fira+Sans+Condensed:wght@300;400;700;800&family=Fira+Sans:wght@200;300;400;700&family=Fira+Sans+Extra+Condensed:wght@300;700&display=swap');
 @import url('https://code.cdn.mozilla.net/fonts/fira.css');
+// Fira Code: the monospaced Fira Sans variant for highlighted/code text (as
+// in the IDS reference decks; falls back to Fira Mono from the Mozilla CSS
+// above, then DejaVu Sans Mono)
+@import url('https://fonts.googleapis.com/css2?family=Fira+Code:wght@300..700&display=swap');
 @import url('https://korap.ids-mannheim.de/font/libertinus.css');
 
 $idsOrange: #f6a800;
@@ -47,6 +51,9 @@
 
 $listBulletColor: $idsOrange;
 
+// --r-code-font (template emits #{$codeFont} as-is)
+$codeFont: "Fira Code", "Fira Mono", "DejaVu Sans Mono", "Source Code Pro", monospace;
+
 // Change text colors against dark slide backgrounds
 @include dark-bg-text-color(#fff);
 
diff --git a/inst/reveal.js-5.2.1/dist/theme/ids.css b/inst/reveal.js-5.2.1/dist/theme/ids.css
index 08aafc8..b7879a9 100644
--- a/inst/reveal.js-5.2.1/dist/theme/ids.css
+++ b/inst/reveal.js-5.2.1/dist/theme/ids.css
@@ -5,6 +5,10 @@
  */
 @import url("https://code.cdn.mozilla.net/fonts/fira.css");
 @import url("https://fonts.googleapis.com/css2?family=Fira+Sans+Condensed:wght@300;400;700;800&family=Fira+Sans:wght@200;300;400;700&family=Fira+Sans+Extra+Condensed:wght@300;700&display=swap");
+/* Fira Code: the monospaced Fira Sans variant for highlighted/code text
+   (as in the IDS reference decks; falls back to Fira Mono from the Mozilla
+   CSS above, then DejaVu Sans Mono) */
+@import url("https://fonts.googleapis.com/css2?family=Fira+Code:wght@300..700&display=swap");
 @import url("https://korap.ids-mannheim.de/font/libertinus.css");
 
 section.has-dark-background, section.has-dark-background h1, section.has-dark-background h2, section.has-dark-background h3, section.has-dark-background h4, section.has-dark-background h5, section.has-dark-background h6 {
@@ -33,7 +37,7 @@
   --r-heading2-size: 1.35em;
   --r-heading3-size: 0.9em;
   --r-heading4-size: 0.7em;
-  --r-code-font: monospace;
+  --r-code-font: "Fira Code", "Fira Mono", "DejaVu Sans Mono", "Source Code Pro", monospace;
   --r-link-color: #2a76dd;
   --r-link-color-dark: #1a53a1;
   --r-link-color-hover: #6ca0e8;