Index: gc_lang/fr/webext/content_scripts/message_box.css
==================================================================
--- gc_lang/fr/webext/content_scripts/message_box.css
+++ gc_lang/fr/webext/content_scripts/message_box.css
@@ -1,11 +1,11 @@
 /*
     CSS
     Message box for Grammalecte
 */
 
-.grammalecte_message_box {
+div.grammalecte_message_box {
     all: initial;
     position: fixed;
     padding: 0;
     margin: 0;
     top: 50%;
@@ -25,40 +25,40 @@
     line-height: normal;
     text-shadow: none;
     text-decoration: none;
     text-align: left;
 }
-.grammalecte_message_box img {
+div.grammalecte_message_box img {
     display: inline-block;
     margin: 0;
     padding: 0;
 }
 
-.grammalecte_message_box_bar {
+div.grammalecte_message_box_bar {
     position: sticky;
     width: 100%;
     background-color: hsl(210, 50%, 50%);
     border-radius: 10px 10px 0 0;
     border-bottom: 1px solid hsl(210, 50%, 47%);
     color: hsl(0, 10%, 92%);
     font-size: 20px;
 }
-.grammalecte_message_box_title {
+div.grammalecte_message_box_title {
     padding: 10px 20px;
 }
-.grammalecte_message_box_label {
+div.grammalecte_message_box_label {
     display: inline-block;
     padding: 0 10px;
 }
-.grammalecte_message_box_invisible_marker {
+div.grammalecte_message_box_invisible_marker {
     position: absolute;
     /*visibility: hidden;*/
     font-size: 6px;
     color: hsl(210, 50%, 50%); /* same color than panel_bar background */
 }
 
-.grammalecte_message_box_content {
+div.grammalecte_message_box_content {
     height: calc(100% - 55px); /* panel height - title_bar */
     padding: 20px;
     color: hsl(0, 50%, 96%);
     font-size: 18px;
 }