Link tag
<link href="http://fonts.googleapis.com/css?family=Open+Sans" rel="stylesheet" type="text/css" />
CSS import
/* One font */
@import url('https://fonts.googleapis.com/css?family=Open+Sans:400,700');
/* Combining multiple fonts */
@import url('https://fonts.googleapis.com/css?family=Open+Sans:400,400italic|Montserrat:400,700'');
Great for using with Codepen.io or similar websites!