diff --git a/src/utils/prosemirror/schema/marks.ts b/src/utils/prosemirror/schema/marks.ts
index 7f434cbe..7e063dad 100644
--- a/src/utils/prosemirror/schema/marks.ts
+++ b/src/utils/prosemirror/schema/marks.ts
@@ -132,7 +132,7 @@ const fontname: MarkSpec = {
   toDOM: mark => {
     const { fontname } = mark.attrs
     let style = ''
-    if (fontname) style += `font-family: ${fontname};`
+    if (fontname) style += `font-family: "${fontname}";`
     return ['span', { style }, 0]
   },
 }