diff --git a/app/assets/stylesheets/swf_assets/show.css b/app/assets/stylesheets/swf_assets/show.css
index 0c1ba8f5..591f951d 100644
--- a/app/assets/stylesheets/swf_assets/show.css
+++ b/app/assets/stylesheets/swf_assets/show.css
@@ -4,9 +4,6 @@
 	position: absolute;
 	left: 0;
 	top: 0;
-
-	/* HACK: `calc` isn't needed, but works around a bug in our asset pipeline,
-	 * where libsass is trying to preprocess it. (We're not SASS tho?) */
-	width: calc(min(100vw, 100vh));
-	height: calc(min(100vw, 100vh));
+	width: min(100vw, 100vh);
+	height: min(100vw, 100vh);
 }
diff --git a/config/application.rb b/config/application.rb
index 74392543..81d27eee 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -58,6 +58,7 @@ module OpenneoImpressItems
     config.assets.paths << Rails.root.join('app', 'assets', 'fonts')
     config.assets.precompile << '*.js'
     config.assets.initialize_on_precompile = false
+    config.assets.css_compressor = nil # Sass's compressor can't handle all modern CSS…
 
     config.middleware.insert_after ActionDispatch::Flash, Rack::Attack