diff --git a/src/js/contentscript.js b/src/js/contentscript.js
index 211ed881a..b66a2fb82 100644
--- a/src/js/contentscript.js
+++ b/src/js/contentscript.js
@@ -209,7 +209,7 @@ vAPI.domFilterer = {
         if ( this.newCSSRules.length ) {
             styleTag = document.createElement('style');
             styleTag.setAttribute('type', 'text/css');
-            styleTag.textContent = ':root ' + this.newCSSRules.join(',\n:root ');
+            styleTag.textContent = ':root ' + this.newCSSRules.join('\n:root ');
             document.head.appendChild(styleTag);
             this.styleTags.push(styleTag);
             this.newCSSRules.length = 0;
diff --git a/src/js/cosmetic-filtering.js b/src/js/cosmetic-filtering.js
index 2b974249e..4fd41c57f 100644
--- a/src/js/cosmetic-filtering.js
+++ b/src/js/cosmetic-filtering.js
@@ -388,6 +388,10 @@ FilterParser.prototype.translateAdguardCSSInjectionFilter = function(raw) {
     if ( matches === null ) {
         return '';
     }
+    // For now we do not allow generic CSS injections (prolly never).
+    if ( matches[1] === '' && matches[2] !== '@' ) {
+        return '';
+    }
     return matches[1] +
            '#' + matches[2] + '#' +
            matches[3].trim() +