JSFiddle - React, Tailwind, and code Playground

HTML

<a id="outer-signup-button" href="#">Sign Up</a>
    <div id="promo-banner">
        <img src="http://i.imgur.com/hbmm3.png" width="129" height="167" />
        <h1>Developers, <span>Imagine</span> your code writing itself</h1>
        <p>Your code compiles without errors, grats!</p>
        <p>It's always the little things that take the longest</p>
        <p>Like figuring out how to mask a div with SVGs</p>
        <p>Totally worth it for learning how SVG works though</p>
        <h2 id="promo-banner-sub-header">Drink to forget the pain!</h2>
        <a id="promo-signup-button" href="#">Developer Sign Up</a>
    </div>

<svg version="1.1" xmlns="http://www.w3.org/2000/svg">
  <defs>
    <mask id="mask-demo" maskUnits="userSpaceOnUse"> 
      <path fill="white" d="m80,148c39,63 166,-255 168,-100c2,155 -24,137 -178,33c-154,-104 10,67 10,67z" stroke-width="5" stroke="#000000" fill="#ffffff"/>
    </mask>
  </defs>
</svg>

CSS

body {
    position: relative;
    background: #444444;
    width: 700px;
}

a#outer-signup-button
{
    position: absolute;
    right: 40px;
    width: 172px;
    height: 32px;
    border-radius:5px;
    -moz-border-radius:5px;
    background: -webkit-gradient(linear, left top, left bottom, from(#F7B400), to(#D76A00));
    background: -moz-linear-gradient(top,  #F7B400,  #D76A00);
    -moz-box-shadow: 0 0 3px rgba(255,255,255,0.35);
    -webkit-box-shadow: 0 0 3px rgba(255,255,255,0.35);
    box-shadow: 0 0 3px rgba(255,255,255,0.35);
    z-index: 2;
    color: #FFFFFF;
    font-weight: bold;
    font-size: 14px;
    text-shadow: #CC5200 0px -1px 0px;
    text-decoration: none;
    text-align: center;
    line-height: 32px;
}

div#promo-banner
{
    position:relative;
    height: 169px;
    width: 669px;
    border-radius:5px;
    -moz-border-radius:5px;
    background: -webkit-gradient(linear, left top, left bottom, from(#2E2E2E), to(#000000));
    background: -moz-linear-gradient(top,  #2E2E2E,  #000000);
    margin: 20px 10px 0px 13px;
    -webkit-mask-box-image: url(http://i.imgur.com/JGTYi.png);
    mask: url(#mask-demo);
    -moz-box-shadow: inset 0 0 3px rgba(255,255,255,0.45);
    -webkit-box-shadow: inset 0 0 3px rgba(255,255,255,0.45);
    box-shadow: inset 0 0 3px rgba(255,255,255,0.45);
}

#promo-banner img
{
    position: absolute;
    bottom: 1px;
    left: 1px;
    border-radius:5px 0px 0px 5px;
    -moz-border-radius:5px 0px 0px 5px;
}

#promo-banner h1
{
    margin-left: 112px;
    font-size: 16px;
    font-weight: normal;
    line-height: 46px;
    color: #FFFFFF;
}

#promo-banner h1 span
{
    font-family: "Times New Roman", Times, serif;
    font-style: italic;
    font-size: 18px;
}

#promo-banner p
{
    margin-left: 142px;
    padding-left: 15px;
    line-height: 16px;
    font-size: 12px;
    color: #CCCCCC;
}

#promo-banner h2
{
    position: absolute;
    font-family: "Times New Roman", Times, serif;
    font-style: italic;
    top:...