.jumbotron {
background-image: url(background.jpg);
color: white;
text-align: center;
}
<div class="jumbotron">
<h1 class="display-4">My Awesome App</h1>
<p class="lead">This is why you should download this fantastic app!</p>
<p>Want to know more?</p>
<p>Join our mailing list!</p>
<hr>
<form class="form-inline" id="jumbo-form">
<div class="form-group mx-sm-3 mb-2">
<input type="password" class="form-control" id="email" placeholder="Email">
</div>
<button type="submit" class="btn btn-primary mb-2">Sign Up Now</button>
</form>
</div>
In the class of jumbotron, all content before the form is centered. However, the form is align left. I tried the solutions from other questions like adding absolute position and then margin:auto but still not working.