Untitled

<!DOCTYPE html>
    <html lang="en">
    <head>
    	<meta charset="UTF-8">
    	<title>Document</title>
    </head>
    <style>
      .triangle {
        display: block;
        width: 0;
        height: 0;
        border-top: 100px solid transparent;
        border-right: 100px solid transparent;
        border-left: 100px solid transparent;
        border-bottom: 100px solid black;
      }
    </style>
    <body>
    	<div class="triangle"></div>
    </body>
    </html>