Bootstrap cards not showing like in examples

Question

Why do my Bootstrap cards look weird? In the examples they look like cards with a border and white padding but mine look like text only without the padding and the white background.

For example:

I don't know if the code will help you but here it is:

.container {
  left: 0;
  right: 0;
  bottom: -340px;
  text-align: middle;
  position: absolute;
}

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
<div class="container">
  <div class="row">
    <div class="col-md-3">
      <div class="card">
        <img class="card-img-top" src="http://www.themdfactor.com/wp-content/uploads/2015/09/card1.jpg" alt="Card image cap">
        <div class="card-block">
          <h4 class="card-title">This is Card #1</h4>
          <p class="card-text">Some quick example text to build on the card title and make up the bulk of the card's content.</p>
          <a href="http://v4-alpha.getbootstrap.com/components/card/" class="btn btn-primary">Learn More</a>
        </div>
      </div>
    </div>
  </div>
</div>

Answer 1

It shows up fine by me. You have to make sure that you are linking the version 4 style sheet.

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.2/css/bootstrap.min.css" integrity="sha384-y3tfxAZXuh4HwSYylfB+J125MxIs6mR5FOHamPBG064zB+AFeWH94NdvaCBm8qnd" crossorigin="anonymous">