diff --git a/src/Magnum/Platform/Test/EmscriptenApplicationTest.cpp b/src/Magnum/Platform/Test/EmscriptenApplicationTest.cpp
index 7b2563b65..4ad684d6e 100644
--- a/src/Magnum/Platform/Test/EmscriptenApplicationTest.cpp
+++ b/src/Magnum/Platform/Test/EmscriptenApplicationTest.cpp
@@ -101,7 +101,7 @@ struct EmscriptenApplicationTest: Platform::Application {
             stopTextInput();
         } else if(event.key() == KeyEvent::Key::F) {
             Debug{} << "toggling fullscreen";
-            setContainerCssClass((_fullscreen ^= true) ? "fullsize" : "");
+            setContainerCssClass((_fullscreen ^= true) ? "mn-fullsize" : "");
         } else if(event.key() == KeyEvent::Key::T) {
             Debug{} << "setting window title";
             setWindowTitle("This is a UTF-8 Window Title™!");
diff --git a/src/Magnum/Platform/Test/EmscriptenApplicationTest.html b/src/Magnum/Platform/Test/EmscriptenApplicationTest.html
index f4e616e0a..5acdbfe99 100644
--- a/src/Magnum/Platform/Test/EmscriptenApplicationTest.html
+++ b/src/Magnum/Platform/Test/EmscriptenApplicationTest.html
@@ -8,11 +8,11 @@
 </head>
 <body>
   <h1>Magnum EmscriptenApplication Test</h1>
-  <div id="container" class="">
-    <div id="sizer"><div id="expander"><div id="listener">
-      <canvas id="canvas" tabindex="0"></canvas>
-      <div id="status">Initialization...</div>
-      <div id="status-description"></div>
+  <div class="mn-container">
+    <div class="mn-sizer"><div class="mn-expander"><div class="mn-listener">
+      <canvas class="mn-canvas" id="canvas" tabindex="0"></canvas>
+      <div class="mn-status" id="status">Initialization...</div>
+      <div class="mn-status-description" id="status-description"></div>
       <script src="EmscriptenApplication.js"></script>
       <script async="async" src="PlatformEmscriptenApplicationTest.js"></script>
       <script>
diff --git a/src/Magnum/Platform/Test/Sdl2ApplicationTest.cpp b/src/Magnum/Platform/Test/Sdl2ApplicationTest.cpp
index 0a645a545..b3660534e 100644
--- a/src/Magnum/Platform/Test/Sdl2ApplicationTest.cpp
+++ b/src/Magnum/Platform/Test/Sdl2ApplicationTest.cpp
@@ -130,7 +130,7 @@ struct Sdl2ApplicationTest: Platform::Application {
         #else
         else if(event.key() == KeyEvent::Key::F) {
             Debug{} << "toggling fullscreen";
-            setContainerCssClass((_fullscreen ^= true) ? "fullsize" : "");
+            setContainerCssClass((_fullscreen ^= true) ? "mn-fullsize" : "");
         }
         #endif
     }
diff --git a/src/Magnum/Platform/Test/Sdl2ApplicationTest.html b/src/Magnum/Platform/Test/Sdl2ApplicationTest.html
index e8086785a..c5fe6d487 100644
--- a/src/Magnum/Platform/Test/Sdl2ApplicationTest.html
+++ b/src/Magnum/Platform/Test/Sdl2ApplicationTest.html
@@ -8,11 +8,11 @@
 </head>
 <body>
   <h1>Magnum Sdl2Application Test</h1>
-  <div id="container">
-    <div id="sizer"><div id="expander"><div id="listener">
-      <canvas id="canvas" tabindex="0"></canvas>
-      <div id="status">Initialization...</div>
-      <div id="status-description"></div>
+  <div class="mn-container">
+    <div class="mn-sizer"><div class="mn-expander"><div class="mn-listener">
+      <canvas class="mn-canvas" id="canvas" tabindex="0"></canvas>
+      <div class="mn-status" id="status">Initialization...</div>
+      <div class="mn-status-description" id="status-description"></div>
       <script src="EmscriptenApplication.js"></script>
       <script async="async" src="PlatformSdl2ApplicationTest.js"></script>
       <script>
diff --git a/src/Magnum/Platform/Test/WindowlessEglApplicationTest.html b/src/Magnum/Platform/Test/WindowlessEglApplicationTest.html
index 7b85893d3..a5ed6d0c6 100644
--- a/src/Magnum/Platform/Test/WindowlessEglApplicationTest.html
+++ b/src/Magnum/Platform/Test/WindowlessEglApplicationTest.html
@@ -8,12 +8,12 @@
 </head>
 <body>
   <h1>Magnum WindowlessEglApplication Test</h1>
-  <div id="container" class="">
-    <div id="sizer"><div id="expander"><div id="listener">
-      <canvas id="canvas" class="hidden"></canvas>
-      <pre id="log"></pre>
-      <div id="status">Initialization...</div>
-      <div id="status-description"></div>
+  <div class="mn-container">
+    <div class="mn-sizer"><div class="mn-expander"><div class="mn-listener">
+      <canvas class="mn-canvas mn-hidden" id="canvas"></canvas>
+      <pre class="mn-log" id="log"></pre>
+      <div class="mn-status" id="status">Initialization...</div>
+      <div class="mn-status-description" id="status-description"></div>
       <script src="WindowlessEmscriptenApplication.js"></script>
       <script async="async" src="PlatformWindowlessEglApplicationTest.js"></script>
     </div></div></div>
