How to align center elements in this CodePen? - html

Question

http://codepen.io/leongaban/pen/ACJta
^ Updated (I can never get SASS to work right in Codepen)
Can't align to the middle my elements above. Using SASS, I want to avoid using position hacks
<main>
<div class="gradient">
<div class="hero">
<img src="http://placehold.it/350x150" alt=""/>
</div>
</div>
<section class="tagline">
<h1>Hi there Lorem Ipsum <em>My name is Bob</em></h1>
<button>Learn More</button>
</section>
</main>
body {
font-family:Arial
}
.hero {
display: table-cell;
//position: relative;
margin: 0 auto;
// top: 42%;
// left: 10%;
text-align: center;
width: auto;
height: 447px;
vertical-align: bottom;
img {
width: 300px;
height: 280px;
text-align: center;
vertical-align: bottom;
border:0;
}
}
.tagline {
position: relative;
margin: 0 auto;
width: 100%;
height: 300px;
text-align: center;
color: blue;
background: gray;
z-index: 2;
h1 {
margin: 0 auto;
padding-top: 5%;
width: 80%;
font-size: 42px;
text-align: center;
}
em {
font-weight: bold;
}
button {
margin-top: 25px;
padding: 10px 20px;
font-family: Arial;
font-size: em(21);
color: white;
border: 0;
background: orange;
}
}

Answer 1

I was able to center your elements above my doing the following:
.hero {
margin: 0 auto;
text-align: center;
width: 50%;
height: 447px;
vertical-align: bottom;
}
It seems it did not want to center because you had specified width: auto