JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html> 
<html lang="en"> 
<head> 
<meta charset="utf-8" /> 
<title>Document Title</title> 
<link rel="stylesheet" href="main.css" type="text/css" /> 
<!--[if lte IE 7]>
<style>
    div#content {
        overflow: hidden;
    }
    div.content_columns {
        vertical-align: top;
        display: inline;
        zoom:1;
        padding-bottom: 9999px;
        margin-bottom: -9999px;
    }
</style>
<![endif]-->
</head> 
<body id="index"> 
<div id="wrapper"> 
    <div id="my_menu"> 
    FIXED MENU WIDTH 100% 
    </div> 
    <div id="my_header"> 
    HEADER WIDTH 100% 
    </div> 
    <div id="content"> 
        <p>CONTENT 960px</p><!--
        --><div id="col1" class="content_columns"> 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        COLUMN 1 WIDTH 320px HEIGHT 100% 
        </div><!--
        --><div id="col2" class="content_columns"> 
        COLUMN 2 WIDTH 320px HEIGHT 100% 
        COLUMN 2 WIDTH 320px HEIGHT 100% 
   ...

CSS

* /* For CSS Reset */ 
{ 
padding: 0; 
margin: 0; 
} 

html, body 
{ 
width: 100%; 
height: 100%; 
} 

div#wrapper 
{ 
width: 100%; 
height: 100%; 
min-height: 100%; /* For Sticky Footer */ 
height: auto !important; /* For Sticky Footer */ 
margin: 0 auto -70px; /* For Sticky Footer */ 
} 

div#my_menu 
{ 
width: 100%; 
height: 50px; 
outline: 1px solid black; 
background-color: grey; 
text-align: center; 
position: fixed; 
} 

div#my_header 
{ 
width: 100%; 
height: 100px; 
outline: 1px solid black; 
background-color: yellow; 
text-align: center; 
padding-top: 50px; 
} 

div#content 
{ 
width: 960px; 
margin: 0 auto; 
outline: 1px solid black; 
background-color: brown; 
text-align: center; 
} 

div.content_columns 
{ 
width: 320px; 
outline: 1px solid black; 
background-color: gold; 
text-align: center; 
display: table-cell;
} 

div.clear_floats /* For Clearing Floats */ 
{ 
clear: both; 
} 

div#my_footer 
{ 
width: 100%; 
height: 70px; 
outline: 1px solid black; 
background-color: pink; 
text-align: center; 
} 

div.push /* For Sticky Footer */ 
{ 
height: 70px; 
}