diff --git a/book/sourdough.sty b/book/sourdough.sty
index fe2f1ca..d38a7cd 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
diff --git a/book/style.css b/book/style.css
index b0ee324..ad0a49e 100644
--- a/book/style.css
+++ b/book/style.css
@@ -1,5 +1,3 @@
-@import url('https://fonts.googleapis.com/css2?family=Open+Sans:wght@400;800&display=swap');
-
 :root{
   --ff-sans: 'Open Sans', sans-serif;
   --fw-regular: 400;
@@ -147,7 +145,6 @@ nav.TOC a, nav.TOC a:visited{
 /* *** Colors *** */
 /* ************** */
 
-
 body{
   background-color: var(--c-beige);
 }
@@ -254,6 +251,10 @@ figcaption.caption {
   display: block;
 }
 
+.chapterToc a, .chapterToc, .likechapterToc a, .likechapterToc, .appendixToc a, .appendixToc, .addchapToc a {
+  font-weight: var(--fw-bold);
+}
+
 @media (max-width: 768px) {
   .toggle-menu-label {
     display: block;
@@ -317,7 +318,7 @@ figcaption.caption {
     display: block;
     color: #000;
     font-size: 20px;
-    font-weight: bold;
+    font-weight: var(--fw-bold);
   }
 
   .chapterToc a, .sectionToc a, .subsectionToc a, .likechapterToc a {
@@ -498,7 +499,7 @@ blockquote {
   border: 2px solid var(--c-black);
   color: var(--c-black);
   padding: 4px;
-  font-weight: bold;
+  font-weight: var(--fw-bold);
   text-decoration: none;
 }
 .crosslinks-bottom a.prev {
diff --git a/book/tex4ebook.cfg b/book/tex4ebook.cfg
index 43adcf5..dffea80 100644
--- a/book/tex4ebook.cfg
+++ b/book/tex4ebook.cfg
@@ -11,4 +11,12 @@
 \Configure{AddCss}{book-ebook.css}
 \Configure{CoverMimeType}{image/jpeg}
 \CoverMetadata{cover/cover-page.jpg}
+\AddToHook{env/tikzpicture/begin}{\fontfamily{opensans-TLF}\selectfont}
+\Configure{@HEAD}{\HCode{
+<style type="text/css">
+  @import url('https://fonts.cdnfonts.com/css/open-sans');
+  body{
+    font-family: 'Open Sans';
+  }
+</style>}}
 \EndPreamble
diff --git a/book/website.cfg b/book/website.cfg
index aa15921..f236b6e 100644
--- a/book/website.cfg
+++ b/book/website.cfg
@@ -9,6 +9,14 @@
 }} 
 
 \Configure{AddCss}{style.css}
+\AddToHook{env/tikzpicture/begin}{\fontfamily{opensans-TLF}\selectfont}
+\Configure{@HEAD}{\HCode{
+<style type="text/css">
+  @import url('https://fonts.cdnfonts.com/css/open-sans');
+  body{
+    font-family: 'Open Sans';
+  }
+</style>}}
 \ConfigureEnv{titlepage}{\ifvmode\IgnorePar\fi\EndP\HCode{<main class="titlepage">}}{\ifvmode\IgnorePar\fi\EndP\HCode{</main>}}{}{}
 
 % Mini TOC