diff --git a/biscuit/apps/chronos/templates/chronos/tt_lesson.html b/biscuit/apps/chronos/templates/chronos/tt_lesson.html
index 104fa31980ae4ef007dce7e65bac714489ba9b1e..bd58b5cb110e50274c54eca82b63a2f0ca5073d2 100644
--- a/biscuit/apps/chronos/templates/chronos/tt_lesson.html
+++ b/biscuit/apps/chronos/templates/chronos/tt_lesson.html
@@ -1,4 +1,4 @@
-<div class="card"
+<div class="card chronos-lesson"
  style="
   {% if lesson_period.lesson.subject.colour_fg %}
    color: {{ lesson_period.lesson.subject.colour_fg }};
diff --git a/biscuit/apps/chronos/templates/chronos/tt_week.html b/biscuit/apps/chronos/templates/chronos/tt_week.html
index b2bed204f5336bbb2a0fc7094d6455714ab0799a..dc9052adcace27643e2f5927e82e7cc2b6bec5cd 100644
--- a/biscuit/apps/chronos/templates/chronos/tt_week.html
+++ b/biscuit/apps/chronos/templates/chronos/tt_week.html
@@ -20,7 +20,7 @@
     {% for num, times in periods.items %}
      <div class="row">
       <div class="col-sm">
-       <div class="card" style="width: 18rem; {% if lesson.colour_fg %} color: {{ lesson.colour_fg }}; {% endif %} {% if lesson.colour_bg %} background-color: {{ lesson.colour_bg }}; {% endif %}">
+       <div class="card chronos-lesson">
         <div class="card-body">
          <div class="row">
           <div class="col-sm">