JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <link rel="stylesheet" href="css/style.css" />
        <link rel="stylesheet" href="css/normalize.css" />
        <!--[if lt IE 9]> 
        <script src="http://html5shiv.googlecode.com/svn/trunk/html5.js"></script> 
        <![endif]-->
    </head>
    <body>
        <div class="wrap">
            <div class="nav">
                <ul class="menu">
                    <li>Главная</li>
                    <li>Отзывы</li>
                    <li>Оставить заявку</li>
                    <li>Контакты</li>
                </ul>
            </div>
            <div class="leftCol"></div>
            <div class="rightCol"></div>
            <div class="center"></div>
        </div>
    </body>
</html>

CSS

@charset "utf-8";

* {
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}

body {
    background: #000;
}

.wrap {
    height: 450px; 
    width: 960px; 
    background: #000;
    position: absolute; 
    top:50%; 
    left: 50%; 
    margin-left: -480px; 
    margin-top:-225px;
    overflow: auto;
}

.clearfix:after {
    content: "."; 
    display: block;  
    clear: both;
    visibility: hidden;
    height: 0; 
}

.box {
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}

.nav {
}

.menu {
    list-style: none;
    margin: 0;
    padding: 0;
}

.menu li {
    float: left;
    width: 245px;
    text-align: center;
    background-color: green;
}

.menu li:first-child, li:last-child {
    width: 235px;
}

.menu:after {
    content: "."; 
    display: block;  
    clear: both;
    visibility: hidden;
    height: 0; 
}

.leftCol, .rightCol, .center {
    background-color: #FFF;
    border-radius: 0 0 25px 25px;
    border: 5px solid green;
    height: 431px;
}

.leftCol {    
    width: 235px; 
    float: left;
}

.rightCol {
    width: 235px; 
    float: right
}

.center {
    width: 490px; 
    margin: 0 auto
}