diff --git a/book.toml b/book.toml
index a6ac995b..8f65b430 100644
--- a/book.toml
+++ b/book.toml
@@ -31,7 +31,7 @@ output-file = "rust-course.pdf"
 pdf-engine = "tectonic"
 pdf-engine-opt = ["-Z", "continue-on-errors"]
 to = "pdf"
-variables = { mainfont = "Noto Sans CJK SC", sansfont = "Noto Sans CJK SC", CJKmainfont = "Noto Sans CJK SC", monofont = "DejaVu Sans Mono" }
+variables = { mainfont = "Noto Sans CJK SC", sansfont = "Noto Sans CJK SC", CJKmainfont = "Noto Sans CJK SC", monofont = "DejaVu Sans Mono", monofontfallback = ["DejaVu Sans Mono:", "Noto Color Emoji:"], mainfontfallback = ["Noto Sans CJK SC:", "Noto Color Emoji:"] }
 
 [output.pandoc.profile.epub]
 output-file = "rust-course.epub"