Fix issue with CSS

assets/css/lesson.scss

@@ -59,7 +59,7 @@ $color-testimonial: #fc8dc1 !default;
 .language-python pre,
 .r pre,
 .language-r pre,
-.sql pre {
+.sql pre ,
 .language-sql pre {
   border-radius: 0 4px 4px 0;
 }