index.php

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css" integrity="sha384-PsH8R72JQ3SOdhVi3uxftmaW6Vc51MKb0q5P2rRUpPvrszuE4W1povHYgTpBfshb" crossorigin="anonymous">

<div>
    <div class="row">
        <div class="col-sm">
        </div>
        <div class="col-sm">
            <h1>Material sobre PHP</h1>
        </div>
        <div class="col-sm">
        </div>
    </div>
</div>
<div class="container">
    <div class="row">
        <div class="col-sm">
        </div>
        <div class="col-sm">
            <a class="btn btn-primary" href="/exemplos" role="button">Exemplos de PHP</a>
            <a class="btn btn-primary" href="http://localhost:15000/" role="button">Ecommerce</a>
        </div>
        <div class="col-sm">
        </div>
    </div>
</div>