diff --git a/book/sourdough.sty b/book/sourdough.sty
index fe2f1caf..d38a7cd1 100644
--- a/book/sourdough.sty
+++ b/book/sourdough.sty
@@ -52,8 +52,9 @@
 \DeclareRobustCommand\sbseries{\fontseries{sb}\selectfont}
 % Fonts for accessibility
 \ifdefined\isaccessible
-    \setmainfont{Open Sans}[
-    Scale=MatchLowercase]
+    \usepackage[mathrm=sym]{unicode-math}
+    \setmathfont{Fira Math}[Scale=MatchLowercase]
+    \setmainfont{Open Sans}[Scale=MatchLowercase]
 \else
     \setmainfont{TeX Gyre Pagella}[Scale=1.0] % Or Palatino Linotype, etc.
     % TODO not available on github CI