Demo: https://codepen.io/hiworldjs/pen/PePWYg
Not being able to find a suitable sample code for a legacy top menu that becomes a sidebar in phone screens, I decided to make one myself.
Since Javascript is overkilled, I created a CSS toggle with checkbox+label and armed it with some smooth CSS3 animations for the eyes.
Feel free to download the code and try yourself.
Cheers,
Harry