diff --git a/src/styles-concreteinfo.css b/src/styles-concreteinfo.css
index d3ffd59..8ed8109 100644
--- a/src/styles-concreteinfo.css
+++ b/src/styles-concreteinfo.css
@@ -982,3 +982,20 @@ body.theme-concrete-warm .line-numbers {
   background: #f0ebe4;
   color: #9a9696;
 }
+
+/* Monospace font + ligature toggles — driven by body classes from renderer */
+body.mono-jetbrains {
+  --font-mono-active: 'JetBrains Mono', monospace;
+}
+
+body.mono-fira {
+  --font-mono-active: 'Fira Code', monospace;
+}
+
+body.mono-ligatures-on {
+  --font-mono-feature: normal;
+}
+
+body.mono-ligatures-off {
+  --font-mono-feature: 'liga' 0, 'calt' 0, 'dlig' 0;
+}
diff --git a/src/styles/tokens.css b/src/styles/tokens.css
index 5459add..92937c4 100644
--- a/src/styles/tokens.css
+++ b/src/styles/tokens.css
@@ -95,6 +95,8 @@
 
   --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
   --font-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', Monaco, 'Courier New', monospace;
+  --font-mono-active: 'JetBrains Mono', monospace;
+  --font-mono-feature: 'liga' 0, 'calt' 0, 'dlig' 0;
 
   --text-xs: 0.75rem;
   --text-sm: 0.875rem;