diff --git a/src/documents/diagram.rs b/src/documents/diagram.rs
index 8904066..e4bea73 100644
--- a/src/documents/diagram.rs
+++ b/src/documents/diagram.rs
@@ -54,7 +54,7 @@ impl Asset for Drawer {
         let renderer = cx.svg_renderer();
         async move {
             let svg = svg(&chart)?;
-            let tree = usvg::Tree::from_data(svg.as_bytes(), &usvg::Options::default())
+            let tree = usvg::Tree::from_data(svg.as_bytes(), &options())
                 .map_err(|error| SharedString::from(format!("{error}")))?;
             let shape = size(px(tree.size().width()), px(tree.size().height()));
             let picture = renderer
@@ -107,13 +107,17 @@ pub fn diagram_svg(source: &str) -> Result<String, SharedString> {
     flatten(&svg(&chart)?)
 }
 
-/// `svg` with markers and text as paths any reader draws.
-pub(crate) fn flatten(svg: &str) -> Result<String, SharedString> {
-    let options = usvg::Options {
+/// usvg reading with the system's fonts.
+pub(crate) fn options() -> usvg::Options<'static> {
+    usvg::Options {
         fontdb: fonts(),
         ..usvg::Options::default()
-    };
-    let tree = usvg::Tree::from_data(svg.as_bytes(), &options)
+    }
+}
+
+/// `svg` with markers and text as paths any reader draws.
+pub(crate) fn flatten(svg: &str) -> Result<String, SharedString> {
+    let tree = usvg::Tree::from_data(svg.as_bytes(), &options())
         .map_err(|error| SharedString::from(format!("{error}")))?;
     // A letter without a font vanishes: say so.
     let (mut kept, mut lost) = (0, 0);
diff --git a/src/documents/mod.rs b/src/documents/mod.rs
index 8f33f90..254ada7 100644
--- a/src/documents/mod.rs
+++ b/src/documents/mod.rs
@@ -33,8 +33,8 @@ pub(crate) use blocks::source;
 pub use blocks::{Align, BlockData, BlockEditor, BlockEvent, BlockKind, Media};
 pub use contents::outline;
 pub use counts::{ReadingTime, WordCount};
-pub(crate) use diagram::flatten;
 pub use diagram::{Diagram, diagram_svg};
+pub(crate) use diagram::{flatten, options as svg_options};
 pub use document::{
     Attachment, DocumentEvent, DocumentHeading, DocumentLook, LARGEST_READ, MarkdownDocument,
     TableEdit, TableRefusal,
diff --git a/src/typography/math.rs b/src/typography/math.rs
index 87bf6ed..95b9655 100644
--- a/src/typography/math.rs
+++ b/src/typography/math.rs
@@ -180,7 +180,7 @@ fn guarded<T>(lay: impl FnOnce() -> T) -> Result<T, MathError> {
 
 /// `svg` reframed around its ink and layout box.
 fn framed(svg: &str, width: f32, height: f32) -> Result<(String, Size<Pixels>), MathError> {
-    let tree = usvg::Tree::from_data(svg.as_bytes(), &usvg::Options::default())
+    let tree = usvg::Tree::from_data(svg.as_bytes(), &crate::documents::svg_options())
         .map_err(|error| MathError::said(format!("{error}")))?;
     let ink = tree.root().abs_stroke_bounding_box();
     let left = ink.left().min(0.0);