diff --git a/doc/changelog.dox b/doc/changelog.dox
index dae4cc197..3bd4b0c62 100644
--- a/doc/changelog.dox
+++ b/doc/changelog.dox
@@ -90,6 +90,9 @@ See also:
     @ref Platform::Sdl2Application
 -   Implemented missing resize event support in @ref Platform::Sdl2Application
     on @ref CORRADE_TARGET_EMSCRIPTEN "Emscripten"
+-   Ability to modify CSS classes that control layout of
+    @ref CORRADE_TARGET_EMSCRIPTEN "Emscripten" app canvas using
+    @ref Platform::Sdl2Application::setContainerCssClass()
 -   Implemented @ref Platform::GlfwApplication::MouseMoveEvent::buttons() for
     feature parity with @ref Platform::Sdl2Application
 -   Added @ref Platform::Sdl2Application::GLConfiguration::setColorBufferSize() "GLConfiguration::setColorBufferSize()",
diff --git a/src/Magnum/Platform/Sdl2Application.cpp b/src/Magnum/Platform/Sdl2Application.cpp
index 8beb97cf2..e6cf7ecc5 100644
--- a/src/Magnum/Platform/Sdl2Application.cpp
+++ b/src/Magnum/Platform/Sdl2Application.cpp
@@ -531,6 +531,15 @@ Vector2i Sdl2Application::framebufferSize() const {
     return size;
 }
 
+#ifdef CORRADE_TARGET_EMSCRIPTEN
+void Sdl2Application::setContainerCssClass(const std::string& cssClass) {
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Wdollar-in-identifier-extension"
+    EM_ASM_({document.getElementById('container').className = Pointer_stringify($0, $1);}, cssClass.data(), cssClass.size());
+    #pragma GCC diagnostic pop
+}
+#endif
+
 void Sdl2Application::swapBuffers() {
     #ifndef CORRADE_TARGET_EMSCRIPTEN
     SDL_GL_SwapWindow(_window);
diff --git a/src/Magnum/Platform/Sdl2Application.h b/src/Magnum/Platform/Sdl2Application.h
index 4c6387d54..b51d956fe 100644
--- a/src/Magnum/Platform/Sdl2Application.h
+++ b/src/Magnum/Platform/Sdl2Application.h
@@ -626,6 +626,22 @@ class Sdl2Application {
          */
         Vector2 dpiScaling(const Configuration& configuration) const;
 
+        #if defined(CORRADE_TARGET_EMSCRIPTEN) || defined(DOXYGEN_GENERATING_OUTPUT)
+        /**
+         * @brief Set container CSS class
+         *
+         * Assigns given CSS class to the @cb{.html} <div class="container"> @ce.
+         * Useful for example to change aspect ratio of the view or stretch it
+         * to cover the full page. See @ref platforms-html5-layout for more
+         * information about possible values. Note that this replaces any
+         * existing class, to set multiple classes separate them with
+         * whitespace.
+         *
+         * @note Only available on @ref CORRADE_TARGET_EMSCRIPTEN "Emscripten".
+         */
+        void setContainerCssClass(const std::string& cssClass);
+        #endif
+
     protected:
         /**
          * @brief Swap buffers