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 8d56808..1489184 100644
--- a/inst/reveal.js-5.2.1/dist/theme/ids.css
+++ b/inst/reveal.js-5.2.1/dist/theme/ids.css
@@ -969,7 +969,9 @@
   font-family: "Fira Sans Condensed", sans-serif;
   font-size: 16px;
   text-align: left;
-  margin-top: 10px;
+  /* breathing room below the title bar; padding instead of margin, because
+     the vertical-centering wrapper zeroes its first child's margin */
+  padding-top: 18px;
   max-height: 510px;
   font-weight: 400;
   color: #253b43;
@@ -983,13 +985,22 @@
 
 .references .csl-entry {
   color: #888888;
-  margin-bottom: 0.5em;
+  /* the hanging indent visually separates entries; no extra margin needed */
+  margin-bottom: 0;
 }
 
 .csl-entry .csl-authors-year {
-  display: block;
-  font-weight: bold;
-  color: #4d616b;
+  font-weight: 400;
+  color: #253b43;
+}
+
+/* in print/PDF, let long bibliographies flow onto continuation pages
+   instead of being clipped by the on-screen scroll box */
+@media print {
+  .reveal .references {
+    max-height: none !important;
+    overflow: visible !important;
+  }
 }
 
 .reveal code.sourceCode:last-child + pre {
diff --git a/inst/rmarkdown/templates/revealjs_presentation/resources/default.html b/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
index 287082e..5ee7d35 100644
--- a/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
+++ b/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
@@ -872,14 +872,15 @@
 
 $if(theme-ids)$
 <script>
-  // IDS theme: in the bibliography, "Authors (Year):" should form a bold first
-  // line, followed by a line break. Which part of an entry citeproc wraps in
-  // spans/links depends on the entry type, so a CSS "break before first child
-  // element" hack cannot place the break reliably. Wrap the leading text up to
-  // and including the first "):" explicitly instead; entries without a year
-  // marker are left untouched.
+  // IDS theme: in the bibliography, "Authors (Year):" should be set
+  // darker than the rest of the entry, but in normal weight. Which part
+  // of an entry citeproc wraps in spans/links depends on the entry type,
+  // so a CSS "break before first child element" hack cannot mark it
+  // reliably. Wrap the leading text up to and including the first "):"
+  // explicitly instead; entries without a year marker are left untouched.
   (function () {
     document.querySelectorAll('.csl-entry').forEach(function (entry) {
+      if (entry.querySelector('.csl-authors-year')) return;
       var textNodes = [];
       var accumulated = '';
       var children = Array.prototype.slice.call(entry.childNodes);
@@ -907,6 +908,117 @@
     });
   })();
 </script>
+<script>
+  // IDS theme: bibliography slides are tightly packed, so auto-fit them:
+  // try a window of font sizes and, when even the smallest one overflows,
+  // move trailing entries onto automatically created continuation slides.
+  // Only runs once per references slide (when it is first shown, so its
+  // entries are measurable); printing is handled by CSS, which lets long
+  // bibliographies flow across pages.
+  (function () {
+    var SIZES = [18, 17, 16, 15, 14, 13, 12];
+    var SPLIT_SIZE = 14;
+
+    function footerReserve() {
+      var v = parseFloat(getComputedStyle(document.documentElement)
+        .getPropertyValue('--ids-footer-reserve'));
+      return isNaN(v) ? 48 : v;
+    }
+
+    function availableHeight(ref) {
+      var slide = ref.closest('section');
+      if (!slide || !slide.clientHeight) return 0;
+      return Math.min(
+        slide.clientHeight - ref.offsetTop - footerReserve() - 10,
+        parseFloat(getComputedStyle(ref).maxHeight) || Infinity
+      );
+    }
+
+    function fits(ref) {
+      var avail = availableHeight(ref);
+      return avail > 0 && ref.scrollHeight <= avail + 1;
+    }
+
+    function splitOff(ref) {
+      ref.style.fontSize = SPLIT_SIZE + 'px';
+      if (fits(ref)) return; // readable again at the split size
+
+      var section = ref.closest('section');
+      var heading = section.querySelector('h1,h2');
+      var title = heading ? heading.textContent : 'References';
+      var avail = availableHeight(ref);
+
+      // measure all entries at the split size, keep those that fit on the
+      // original slide and distribute the rest over continuation slides
+      // with the same geometry
+      var entries = Array.prototype.slice.call(ref.querySelectorAll(':scope > .csl-entry'));
+      var heights = entries.map(function (entry) {
+        return entry.getBoundingClientRect().height +
+          parseFloat(getComputedStyle(entry).marginBottom);
+      });
+      var keep = 0;
+      var used = 0;
+      for (var k = 0; k < entries.length; k++) {
+        if (used + heights[k] > avail) break;
+        used += heights[k];
+        keep = k + 1;
+      }
+      if (keep === 0) keep = 1; // at least one entry stays on the slide
+      if (keep >= entries.length) return; // everything fits after all
+      var stash = entries.slice(keep);
+      stash.forEach(function (entry) { entry.remove(); });
+
+      var pages = [[]];
+      used = 0;
+      stash.forEach(function (entry, i) {
+        var height = heights[keep + i];
+        if (used + height > avail && pages[pages.length - 1].length) {
+          pages.push([]);
+          used = 0;
+        }
+        pages[pages.length - 1].push(entry);
+        used += height;
+      });
+
+      var insertAfter = section;
+      pages.forEach(function (pageEntries, i) {
+        if (!pageEntries.length) return;
+        var cont = document.createElement('section');
+        cont.className = section.className;
+        cont.id = (section.id || 'references') + '-cont-' + (i + 1);
+        if (heading) {
+          var h = document.createElement(heading.tagName);
+          h.textContent = title + ' (cont.)';
+          cont.appendChild(h);
+        }
+        var newRef = ref.cloneNode(false);
+        pageEntries.forEach(function (entry) { newRef.appendChild(entry); });
+        cont.appendChild(newRef);
+        insertAfter.parentNode.insertBefore(cont, insertAfter.nextSibling);
+        insertAfter = cont;
+      });
+      if (typeof Reveal !== 'undefined' && Reveal.isReady()) Reveal.sync();
+    }
+
+    function fitBibliographies() {
+      document.querySelectorAll('.reveal .references').forEach(function (ref) {
+        if (ref.dataset.fitDone) return;
+        if (!ref.closest('section').clientHeight) return; // not laid out yet
+        ref.dataset.fitDone = '1';
+        ref.style.fontSize = '';
+        for (var i = 0; i < SIZES.length; i++) {
+          ref.style.fontSize = SIZES[i] + 'px';
+          if (fits(ref)) return;
+        }
+        splitOff(ref);
+      });
+    }
+
+    Reveal.on('ready', fitBibliographies);
+    Reveal.on('slidechanged', function () { requestAnimationFrame(fitBibliographies); });
+    window.addEventListener('load', fitBibliographies);
+  })();
+</script>
 $endif$
 
 $if(theme-ids)$
@@ -1223,6 +1335,9 @@
     function wrapSlideContent(slide) {
       if (slide.dataset.contentWrapped) return;
       slide.dataset.contentWrapped = '1';
+      // bibliographies stay top-aligned: they are packed anyway, and the
+      // fitting/splitting logic below works from the slide top downwards
+      if (slide.querySelector('.references')) return;
       var content = Array.prototype.filter.call(
         Array.prototype.slice.call(slide.children, headingCount(slide)),
         function (el) { return el.tagName !== 'ASIDE'; }