diff --git a/procedure.typ b/procedure.typ
index 099ae39..b9cb170 100644
--- a/procedure.typ
+++ b/procedure.typ
@@ -73,7 +73,7 @@ where $alpha_B$ is the recombination coefficient, $C$ is the clumping factor, $a
 
 Ionizing photons, i.e. photons with energies above $13.6 "eV"$, experience a large optical depth, which justifies the sharp cutoff of the ionization profile at the bubble radius $R_b = root(3, 3/ (4pi) V(M,z))$. The radial dependence of the ionized fraction is expressed through the Heaviside step function $theta_"H"$ and reads
 $
-x_("HII")(r bar M, z) = theta_"H" lr([R_b (M, z) - r], size: #150%)
+  x_("HII")(r bar M, z) = theta_"H" lr([R_b (M, z) - r], size: #150%)
 $
 
 === Expression of the reionization signal