diff --git a/src/html/index.html b/src/html/index.html
index 01ff3d20..c385dc4c 100644
--- a/src/html/index.html
+++ b/src/html/index.html
@@ -8,7 +8,6 @@
         <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
         <title id="header-title">Ideas - Logic Tools</title>
         <meta name="description" content="">
-        <meta name="viewport" content="width=1020">
 
 		<link rel="stylesheet" href="css/main.css">
 		<script type="module" src="main.bundle.js" type="text/javascript"></script>
@@ -29,6 +28,14 @@
         <ul class="nav" id="myTabs" style="border-bottom: 1px solid #ddd; background-color: #fff"></ul>
 
         <div class="container" style="padding-top: 25px; padding-bottom: 25px">
+            <div class="row" id="no-mobile-alert-container" style="display: none">
+                <div class="alert alert-warning col-12 alert-dismissable" id="no-mobile-alert" role="alert">
+                    <span translate-key="main.noMobile"></span>
+                    <button type="button" class="close" data-dismiss="alert" aria-label="Close">
+                        <span aria-hidden="true">&times;</span>
+                    </button>
+                </div>
+            </div>
 			<div class="row">
 				<div class="col-12">
 		            <div class="tab-content" id="tab-container"></div>
diff --git a/src/html/oneway.html b/src/html/oneway.html
index 1fd0973d..7f063c0f 100644
--- a/src/html/oneway.html
+++ b/src/html/oneway.html
@@ -8,7 +8,6 @@
 	<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
 	<title>Ideas - Conjunctive Normal Form</title>
 	<meta name="description" content="">
-	<!-- <meta name="viewport" content="width=1020"> -->
 
 	<script src="oneWay.bundle.js" type="text/javascript"></script>
 
diff --git a/src/html/onewaysolution.html b/src/html/onewaysolution.html
index 8766d165..fa7977ea 100644
--- a/src/html/onewaysolution.html
+++ b/src/html/onewaysolution.html
@@ -8,7 +8,6 @@
         <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
         <title>Ideas - Solution</title>
         <meta name="description" content="solution">
-        <meta name="viewport" content="width=1020">
 
 		<link rel="stylesheet" href="css/ideas.css">
     </head>
diff --git a/src/html/twoway.html b/src/html/twoway.html
index f19c71a3..6d031f6a 100644
--- a/src/html/twoway.html
+++ b/src/html/twoway.html
@@ -8,7 +8,6 @@
         <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
         <title>Ideas - LogEX</title>
         <meta name="description" content="">
-        <meta name="viewport" content="width=1020">
 
         <script src="twoWay.bundle.js" type="text/javascript"></script>
 
diff --git a/src/html/twowaysolution.html b/src/html/twowaysolution.html
index c4b550a1..b58e2400 100644
--- a/src/html/twowaysolution.html
+++ b/src/html/twowaysolution.html
@@ -8,7 +8,6 @@
         <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
         <title>Ideas - Solution</title>
         <meta name="description" content="solution">
-        <meta name="viewport" content="width=1020">
 
 		<link rel="stylesheet" href="css/ideas.css">
     </head>
diff --git a/src/js/controller/mainFrameController.js b/src/js/controller/mainFrameController.js
index 97c0cab8..a651ad2d 100644
--- a/src/js/controller/mainFrameController.js
+++ b/src/js/controller/mainFrameController.js
@@ -60,6 +60,11 @@ class MainFrameController {
 
       document.getElementById(`fra-${tool.code}`).onload = () => { translateChildren(document.getElementById(`fra-${tool.code}`).contentWindow.document) }
     }
+
+    // No mobile alert
+    if (window.innerWidth < 990) {
+      document.getElementById('no-mobile-alert-container').style.display = ''
+    }
   }
 
   /**
diff --git a/src/lang/en.json b/src/lang/en.json
index 91cb8c31..04fac167 100644
--- a/src/lang/en.json
+++ b/src/lang/en.json
@@ -437,6 +437,7 @@
     "title": "Proving with Structural Induction"
   },
   "main": {
+    "noMobile": "This tool is not optimized for use on screens with a limited width.",
     "tabTitle": {
       "cnf": "Conjunctive Normal Form",
       "dnf": "Disjunctive Normal Form",
diff --git a/src/lang/nl.json b/src/lang/nl.json
index 83b3e791..501971ec 100644
--- a/src/lang/nl.json
+++ b/src/lang/nl.json
@@ -437,6 +437,7 @@
     "title": "Bewijzen met volledige inductie"
   },
   "main": {
+    "noMobile": "Dit programma is niet geoptimaliseerd voor beeldschermen met een beperkte breedte.",
     "tabTitle": {
       "cnf": "Conjunctieve Normaalvorm",
       "dnf": "Disjunctieve Normaalvorm",