“If you just sit and observe, you will see how restless your mind is. If you try to calm it, it only makes it worse, but over time it does calm, and when it does, there’s room to hear more subtle things. You see so much more than you could see before. It’s a discipline; you have to practice it.”
Steve Jobs

:valid

The :valid CSS pseudo-class represents any <input> or other <form> element whose contents validate successfully. This allows to easily make valid fields adopt an appearance that helps the user confirm that their data is formatted properly.
:valid css reference