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 4691a64..7daee42 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
@@ -1001,3 +1001,37 @@
   padding: 0;
 }
 
+
+/*********************************************
+ * OVERVIEW / TOC SLIDES
+ *********************************************/
+/* Entries stay at the normal slide body size and keep the theme's link
+   colour, so they read as the navigation links they are. Only the denser
+   two-column variant with sub-headings is scaled down. */
+.reveal .ids-overview-toc {
+  list-style: none;
+  margin: 0.2em 0 0 0;
+  padding: 0;
+  line-height: 1.35;
+}
+.reveal .ids-overview-toc > li {
+  margin: 0.45em 0;
+  font-weight: bold;
+}
+.reveal .ids-overview-toc ul {
+  list-style: none;
+  margin: 0.1em 0 0.2em 0;
+  padding: 0 0 0 1.1em;
+  font-weight: normal;
+}
+.reveal .ids-overview-toc.with-subheadings {
+  columns: 2;
+  column-gap: 2.5em;
+  font-size: 0.8em;
+}
+.reveal .ids-overview-toc.with-subheadings > li {
+  break-inside: avoid;
+}
+.reveal .ids-overview-toc ul li {
+  margin: 0.18em 0;
+}