diff --git a/docs/src/index.md b/docs/src/index.md
index 39fcc78..4bf6c8b 100644
--- a/docs/src/index.md
+++ b/docs/src/index.md
@@ -26,7 +26,7 @@ Pkg.add("https://github.com/NumericalEarth/Breeze.jl.git")
 
 A basic free convection simulation:
 
-```julia
+```@example intro
 using Oceananigans
 using Oceananigans.Units
 using CairoMakie