html referring to an external style sheet code example
Example 1: add stylesheet html
<link rel="stylesheet" type="text/css" href="style.css">
Example 2: external style sheet
<link rel="stylesheet" type="text/css" href="mystyle.css">
<link rel="stylesheet" type="text/css" href="style.css">
<link rel="stylesheet" type="text/css" href="mystyle.css">