div p:first-child {color:red}
p:hover {color:green;background-color:yellow}
p:lang(fr) {font-style:italic}
input:focus {color:blue;background-color:pink;outline: thick solid black}
. . .
<div>
<p>First paragraph</p>
<p class="first">Second paragraph</p>
<p lang="fr">Je suis ...</p>
<form action="payment.asp" method="post">
  <p>Credit card number:</p>
  <p>Number:<input type="text" name="ccnumber"/></p>
  <p><input type="submit"/></p>
</form>
</div>