Why is the following CSS code not centering my button horizontally within a div element?

Developing with Concrete
1

Why is the following CSS code not centering my button horizontally within a div element? It appears off-center in my webpage:

<!DOCTYPE html>
<html>
<head>
<style>
  .container {
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
  }

  .btn {
    background-color: #3498db;
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
  }
</style>
</head>
<body>

<div class="container">
  <button class="btn">Click Me</button>
</div>

</body>
</html>

The button seems to be slightly toward the left side within the container. What am I missing in the CSS that is preventing the button from being perfectly centered?

2

Is this the actual code? Make sure there is no padding or margins being pulled in from another style sheet.

Inspect the button

3

Looks centered to me in JS Fiddle. Like @TMDesigns is mentioning if you’re seeing weirdness it would have to be coming from another style source.