This solution might be simpler...

...and might not need a complete rewrite of the whole CSS

partitioncloud/static/mobile.css

@@ -13,5 +13,10 @@
         overflow: hidden;
         min-width: 90vw;
         position: fixed;
+        transition: all 0.5s ease;
+    }
+
+    input:checked#slide-sidebar~#content-container {
+        position: initial;
     }
 }

partitioncloud/static/style.css

@@ -81,6 +81,10 @@
     font-family: var(--font-family);
 }
 
+body {
+    overflow-x: hidden;
+}
+
 
 /** Hide scrollbars (deeply needed on Chromium) */
 ::-webkit-scrollbar {
@@ -158,6 +162,7 @@ body {
     transition: left 0.5s ease;
 
     padding: 5px;
+    margin-left: var(--sidebar-size);
 }
 
 .album-cover {
@@ -181,6 +186,9 @@ body {
     top: 0;
     left: 0;
     bottom: 0;
+
+    -moz-transition: width 0.5s ease;
+    transition: width 0.5s ease;
 }
 
 #slide {
@@ -197,11 +205,13 @@ body {
 input:checked#slide-sidebar~#content-container {
     left: 0;
     overflow: unset;
+    margin-left: 0;
 }
 
 input:checked#slide-sidebar~#footer {
     left: 0;
     overflow: unset;
+    margin-left: 0;
 }
 
 input:checked#slide-sidebar~#sidebar {
@@ -397,6 +407,9 @@ img.partition-thumbnail {
     margin: 5px;
 
     border-radius: 3px;
+
+    -moz-transition: width 0.5s ease;
+    transition: width 0.5s ease;
 }
 
 button#logout,
@@ -667,3 +680,7 @@ td {
 .liste {
     text-align: left;
 }
+
+.x-scrollable {
+    overflow-x: auto;
+}

partitioncloud/templates/admin/index.html

@@ -12,7 +12,8 @@
         <div class="button">Voir toutes les partitions</div>
     </a>
 </div>
-<table>
+<div class="x-scrollable">
+    <table>
         <thead>
             <tr>
                 <th scope="col">Utilisateur</th>
@@ -39,5 +40,6 @@
             </tr>
             {% endfor %}
         </tbody>
-</table>
+    </table>
+</div>
 {% endblock %}