diff --git a/src/static/js/ace2_inner.js b/src/static/js/ace2_inner.js
index 9c69fad1..a34b94e5 100644
--- a/src/static/js/ace2_inner.js
+++ b/src/static/js/ace2_inner.js
@@ -975,9 +975,8 @@ function Ace2Inner(){
       showsuserselections: setClassPresenceNamed(root, "userSelections"),
       showslinenumbers : function(value){
         hasLineNumbers = !! value;
-        // disable line numbers on mobile devices
-        if (browser.mobile) hasLineNumbers = false;
         setClassPresence(sideDiv, "sidedivhidden", !hasLineNumbers);
+        setClassPresence(sideDiv.parentNode, "sidediv-hidden", !hasLineNumbers);
         fixView();
       },
       grayedout: setClassPresenceNamed(outerWin.document.body, "grayedout"),
diff --git a/src/static/skins/colibris/src/components/sidediv.css b/src/static/skins/colibris/src/components/sidediv.css
index 74595f54..88193135 100644
--- a/src/static/skins/colibris/src/components/sidediv.css
+++ b/src/static/skins/colibris/src/components/sidediv.css
@@ -1,7 +1,6 @@
 #sidediv {
   background-color: transparent;
   border: none;
-  display: block;
 }
 
 #sidedivinner>div:before {
diff --git a/src/static/skins/colibris/src/layout.css b/src/static/skins/colibris/src/layout.css
index 5f3183eb..88ff98fc 100644
--- a/src/static/skins/colibris/src/layout.css
+++ b/src/static/skins/colibris/src/layout.css
@@ -26,15 +26,18 @@
 }
 
 #outerdocbody.ep_author_neat {
-  padding-left: 120px;
+  padding-left: 120px; /* more space for sidediv */
+}
+
+#outerdocbody.sidediv-hidden {
+  padding-left: 0; /* sidediv hidden */
 }
 
 #outerdocbody iframe {
   display: block;
   position: relative;
   left: 0 !important;
-  top: 0;
-  
+  top: 0;  
 }
 
 #outerdocbody iframe, .timeslider #editorcontainerbox {
@@ -117,7 +120,7 @@
     padding: 15px !important;
     width: calc(100% - 30px) !important; /* 100% - padding */
   }
-  #sidediv { 
+  #sidediv:not(.sidedivhidden) { 
     display: block;
     top: 15px !important; /* = #outerdocbody iframe padding-top */
   }
diff --git a/src/static/skins/no-skin/pad.css b/src/static/skins/no-skin/pad.css
index 236251d9..f300b81c 100644
--- a/src/static/skins/no-skin/pad.css
+++ b/src/static/skins/no-skin/pad.css
@@ -1,8 +1,5 @@
-/*
-  custom css files are loaded after core css files. Simply use the same selector to override a style.
-  Example:
-      #editbar LI {border:1px solid #000;}
-    overrides
-      #editbar LI {border:1px solid #d5d5d5;}
-    from pad.css
-*/
+@media (max-width:600px) {
+  #sidediv { 
+    display: none !important;
+  }
+}
\ No newline at end of file