diff --git a/html/static/style.css b/html/static/style.css
index 8cbf387..677fb49 100644
--- a/html/static/style.css
+++ b/html/static/style.css
@@ -125,6 +125,18 @@ h2:has(.done.FREED), h3:has(.done.FREED), h4:has(.done.FREED), h5:has(.done.FREE
     content: '⮟ ';
 }
 
+.footnote-tooltip {
+    position: 'absolute';
+    z-index:  1000;
+    background-color: var(--background-tooltip);
+    border: 1px solid var(--accent1);
+    border-radius: = 4px;
+    padding: 8px 12px;
+    max-width: 300px;
+    font-size: calc(var(--font-size) * 0.9);
+    box-shadow: 1px 1px 1px var(--grey2);
+}
+
 :root {
     --site-width: 1000px;
     --vert-content-margin: 0.3rem;
diff --git a/org/source.org b/org/source.org
index 4db6c1e..cadbef4 100644
--- a/org/source.org
+++ b/org/source.org
@@ -727,6 +727,21 @@ function enableFootnotes() {
 document.addEventListener('DOMContentLoaded', enableFootnotes);
 #+END_SRC
 
+#+BEGIN_SRC css :tangle ../html/static/style.css
+.footnote-tooltip {
+    position: 'absolute';
+    z-index:  1000;
+    background-color: var(--background-tooltip);
+    border: 1px solid var(--accent1);
+    border-radius: = 4px;
+    padding: 8px 12px;
+    max-width: 300px;
+    font-size: calc(var(--font-size) * 0.9);
+    box-shadow: 1px 1px 1px var(--grey2);
+}
+#+END_SRC
+
+
 
 ** Appearance
 *** Global :autocollapse: