ids theme: fullscreen toggle button for touch devices

Change-Id: I0bd17d0b899faa0f81c692933b3d494678853e12
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 d3cc7ed..ee3b816 100644
--- a/inst/reveal.js-5.2.1/dist/theme/ids.css
+++ b/inst/reveal.js-5.2.1/dist/theme/ids.css
@@ -894,8 +894,38 @@
 }
 
 /*********************************************
- * ARROWS and SLIDE NUMBERS
+ * FULLSCREEN TOGGLE
  *********************************************/
+#ids-fullscreen {
+  display: none;
+  position: fixed;
+  left: 30px;
+  bottom: 6%;
+  z-index: 30;
+  width: 28px;
+  height: 28px;
+  border: 0;
+  padding: 0;
+  cursor: pointer;
+  opacity: 0.55;
+  background: transparent url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23aaaaaa' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M8 3H5a2 2 0 0 0-2 2v3'/%3E%3Cpath d='M16 3h3a2 2 0 0 1 2 2v3'/%3E%3Cpath d='M8 21H5a2 2 0 0 1-2-2v-3'/%3E%3Cpath d='M16 21h3a2 2 0 0 0 2-2v-3'/%3E%3C/svg%3E") center/contain no-repeat;
+}
+#ids-fullscreen:active, #ids-fullscreen:focus-visible {
+  opacity: 0.9;
+}
+#ids-fullscreen.is-fullscreen {
+  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23f6a800' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M8 3H5a2 2 0 0 0-2 2v3'/%3E%3Cpath d='M16 3h3a2 2 0 0 1 2 2v3'/%3E%3Cpath d='M8 21H5a2 2 0 0 1-2-2v-3'/%3E%3Cpath d='M16 21h3a2 2 0 0 0 2-2v-3'/%3E%3C/svg%3E");
+}
+
+@media (hover: none) and (pointer: coarse) {
+  #ids-fullscreen {
+    display: block;
+  }
+}
+html.reveal-print #ids-fullscreen {
+  display: none !important;
+}
+
 .reveal .controls .controls-arrow:after, .reveal .controls .controls-arrow:before {
   width: 13px !important; /* size */
   height: 4px; /* line width */