JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://sencss.kilianvalkhof.com/source/sen.css">
    <div id="wrapper">
        <div id="top"></div>
        <div class="horizontalSpacer"></div>
        <div id="left">
            left
        </div>
        <div id="content">
            content
        </div>
    </div>

CSS

html { background: #cbccc8;}
.horizontalSpacer
{
    width:100%;
    height: 20px;
    clear: both;
}
body { 
    background-repeat: no-repeat;
    background: #cbccc8;
    background: -webkit-gradient(linear, left top, left bottom, from(#fff), to(#cbccc8));
    background: -moz-linear-gradient(top,  #fff,  #cbccc8);
    filter:  progid:DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#cbccc8'); }
#wrapper
{
    min-width:960px;
    margin-left:auto;
    margin-right:auto;
}
#top
{
    width: 100%;
    height: 40px;
    background: rgb(69,72,77);
    background: -moz-linear-gradient(top,  rgba(69,72,77,1) 0%, rgba(0,0,0,1) 100%);
    background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(69,72,77,1)), color-stop(100%,rgba(0,0,0,1)));
    background: -webkit-linear-gradient(top,  rgba(69,72,77,1) 0%,rgba(0,0,0,1) 100%);
    background: -o-linear-gradient(top,  rgba(69,72,77,1) 0%,rgba(0,0,0,1) 100%);
    background: -ms-linear-gradient(top,  rgba(69,72,77,1) 0%,rgba(0,0,0,1) 100%);
    background: linear-gradient(to bottom,  rgba(69,72,77,1) 0%,rgba(0,0,0,1) 100%);
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#45484d', endColorstr='#000000',GradientType=0 );

}
#left
{
    width:200px;
    float:left;
    background-color:antiquewhite;
    margin-left:10px;
}
#content
{
    min-width:700px;
  margin-right: -210px;
    width:100%;
    float:left;
    background-color:AppWorkspace;
}