Also "CSS to make it look pretty. Dont use JavaScript for visual effects." -- Sometimes this cannot be avoided, because css also has its limitation. Especially

Also "CSS to make it look pretty. Dont use JavaScript for visual effects." -- Sometimes this cannot be avoided, because css also has its limitation. Especially when you need to move content around in different elements depending on screen size etc. it's a hell to maintain with css, where as with javascript you can do it in a few lines.