Text fields

HTML

<input type="text" required/><br>
<input type="text" required/>

CSS

input[type="text"] {
  margin: 4px;
  border: 1px solid #aaaaaa;
  border-radius: 3px;
  font-size: 16pt;
  outline: none;
}
input[type="text"]:focus {
  border: 1px solid #add8e6;
  box-shadow: 0px 0px 2px 2px #add8e6;
}

input[type="text"]:valid {
  border: 1px solid #ade6bb;
  box-shadow: 0px 0px 2px 2px #ade6bb;
}