Borders with calc on parent div

by Matthew Day

HTML

<div id="outer">
  <div id="inner">
    <div id="content">
      <div class="contact-title">Inquiries</div>
      <p>[email protected]</p>
      <div class="contact-title">Address</div>
      <p>Vertical Capital, LLC<br>437 Madison Avenue,<br>39th Floor<br>New York, NY 10022</p>
      <div class="contact-title">Phone</div>
      <p>212.786.5300</p>
    </div>
  </div>
</div>

CSS

/* http://meyerweb.com/eric/tools/css/reset/  */
html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend, 
caption, tbody, tfoot, thead,
article, aside, canvas, details, embed, 
figure, figcaption, footer, header, hgroup, 
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
   margin: 0;
   padding: 0;
   border: 0;
   font-size: 100%;
   font: inherit;
   vertical-align: baseline;
}


/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure, 
footer, header, hgroup, menu, nav, section {
	display: block;
}
body {
	line-height: 1;
}
ol, ul {
   list-style: none;
}
blockquote, q {
   quotes: none;
}
blockquote:before, blockquote:after,
q:before, q:after {
   content: '';
   content: none;
}



/* http://www.paulirish.com/2012/box-sizing-border-box-ftw */
*, *:before, *:after {
  -moz-box-sizing: border-box; 
  -webkit-box-sizing: border-box; 
  box-sizing: border-box;
}


/* WebKit tap highlighting */
* {
  -webkit-tap-highlight-color: #000;
}

 
/*  http://www.yuiblog.com/blog/2010/09/27/clearfix-reloaded-overflowhidden-demystified */
.clearfix:before,
.clearfix:after {
    content: '\0020';
    display: block;
    overflow: hidden;
    visibility: hidden;
    width: 0;
    height: 0;
}
.clearfix:after {
    clear: both;
}
.clearfix {
    zoom: 1;
}





* {
    box-sizing: border-box;
}

#outer {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background: #003D71;
}

#inner {
    position: relative;
    width: calc(100% - 20px);
    height: calc(100% - 20px);
    margin: 10px;
    background: #fff;
}

#content {
    position: absolute;
    top: 10px;
    right: 10px;
    bottom: 10px;
    left: 10px;
    padding: 30px 0 0 30px;
    background:...