<!DOCTYPE html>
<html>
<head>
<title>new</title>
<style>
#foo {
color: blue;
}
</style>
</head>
<body>
for example you have two h1 but want to style one of them
to do that give it an Id
<h1 id="foo">first title</h1>
<h1>second title</h1>
</body>
</html>