JSFiddle - React, Tailwind, and code Playground

HTML

<div id="navigation" class="clearfix">
    ...
</div> <!-- /#navigation -->

<div id="header-wrapper">
  <div id="header" class="clearfix<?php if ($page['header']): ?> with-blocks<?php endif; ?>">
    <div id="branding" class="clearfix">
      ...
    </div> <!-- /#branding -->
  </div> <!-- /#header -->
</div>  <!-- /#header-wrapper -->

<div id="main-columns-wrapper">
  <div id="main-columns" class="clearfix">
    <div id="main">
      <div id="page" class="clearfix">
      </div> <!-- /#page -->

      <div id="footer">
        ...
      </div> <!-- /#footer -->
    </div> <!-- /#main -->

    <div id="sidebar-first" class="clearfix">
      ...
    </div> <!-- /#sidebar-first -->

    <div id="sidebar-second" class="clearfix">
      ...
    </div> <!-- /#sidebar-second -->

  </div> <!-- /#main-columns -->
</div> <!-- /#main-columns-wrapper -->

CSS

/**
 * Layout
 */
#main,
#sidebar-first,
#sidebar-second {
  float: left; /* LTR */
}
/* Layout width */
#navigation ul,
#header,
#main-columns {
  margin: 0 auto;
  width: 85%;
  min-width: 960px;
  max-width: 1200px;
}
/*  Column width */
body.two-sidebars #main {
  width: 56%;
}
body.two-sidebars #sidebar-first,
body.two-sidebars #sidebar-second {
  width: 21.9%;
}
body.one-sidebar #main {
  width: 70%;
}
body.one-sidebar #sidebar-first,
body.one-sidebar #sidebar-second {
  width: 29.7%;
}
body.no-sidebars #main {
  width: 100%;
}
/* Spacing between columns */
#sidebar-first .region,
#sidebar-second .region {
  margin: 0 0 0 20px; /* LTR */
}
/* Prevent collision with browser chrome */
#navigation ul,
#header,
#main-columns {
  padding: 0 15px;
}
/* Mobile */
@media only screen and (max-device-width: 480px) {
  #navigation ul,
  #header,
  #main-columns {
    width: 100%!important;
  }
}

/* RTL stylesheet */
#main,
#sidebar-first,
#sidebar-second {
  float: right;
}
#sidebar-first .region,
#sidebar-second .region {
  margin: 0 20px 0 0;
}

/* IE6 stylesheet */
#navigation ul,
#header,
#main-columns {
  width: 960px;
}