include external style sheet code example
Example 1: external css
<html>
<head>
<link rel="stylesheet" type="text/css" href="mystyle.css"></link>
</head>
<body>
Example 2: add css file in html
/*
Adding css file into html document
*/
<link rel="stylesheet" type="text/css" href="yourstylesheetname.css"> /* add this line into head tag of the file with change in file name. */
/*
I hope it will help you.
Namaste
*/