diff --git a/biscuit/apps/chronos/templates/chronos/tt_lesson.html b/biscuit/apps/chronos/templates/chronos/tt_lesson.html
index 86994d3a2a03b1d1fd31084e3a91a85daa824ee0..c138e3f43b084a0bd6b880a380e56fc4b4034bae 100644
--- a/biscuit/apps/chronos/templates/chronos/tt_lesson.html
+++ b/biscuit/apps/chronos/templates/chronos/tt_lesson.html
@@ -2,7 +2,7 @@
 
 <div class="card chronos-lesson
   {% if lesson_period.get_substitution.cancelled %}
-  border border-danger chronos-lesson-cancelled
+    border border-danger chronos-lesson-cancelled
   {% elif lesson_period.get_substitution %}
    border border-warning
   {% endif %}