diff --git a/index.html b/index.html
index 90587f9..f331b26 100644
--- a/index.html
+++ b/index.html
@@ -79,6 +79,14 @@
         <section id="section-2" class="section hidden">
             <button class="button is-link is-light" onclick="switchSection('section-1')">Torna enrere (Classe)</button>
 
+            <div id="repeated-subject-warning" class="hidden">
+                <br><article class="message is-warning">
+                    <div class="message-body">
+                        Heu triat una assignatura que es fa en dues aules alhora. Comproveu que sou a l'aula <strong id="repeated-subject-warning-class">aula</strong>.
+                    </div>
+                </article>
+            </div>
+
             <div id="letter-container" class="buttons grid">
                 <button class="button" id="letter-A" data-letter="A">A</button>
                 <button class="button" id="letter-B" data-letter="B">B</button>