diff --git a/_custom/custom.css b/_custom/custom.css
index 08778c98..91a0bc1f 100644
--- a/_custom/custom.css
+++ b/_custom/custom.css
@@ -37,6 +37,11 @@
   margin-bottom: 24px;
 }
 
+.admonition .admonition {
+    /* Don't keep shrinking the font for nested admonitions. */
+    font-size: 100%;
+}
+
 .admonition p {
   font-size: inherit;
 }