For more icon details, please visit Material Icon official website.
<a class='btn primary lg icons'>star</a>
<a class='btn primary md icons'>school</a>
<a class='btn primary sm icons'>notifications</a>
<a class='btn primary xs icons'>face</a>
<a class='btn secondary lg icons'>star</a>
<a class='btn secondary md icons'>school</a>
<a class='btn secondary sm icons'>notifications</a>
<a class='btn secondary xs icons'>face</a>