JSFiddle - React, Tailwind, and code Playground

HTML

<div id="top_block">$SITE_NAME$</div>
<div id="left_block">Menyu i drugoe</div>
<div id="content_block">Soderzhimoe</div>

CSS

@charset "utf-8";
html, body {
	margin: 0;
	background-color: #181b18;
	color: #fff;
	height: 100%;
}
#top_block {
	position: absolute;
	top: 0;
	left: 0;
	width: 100%;
	background-color: #0c0d0c;
	height: 50px;
}
#left_block {
	background-color: #121412;
	float: left;
	width: 20%;
	height: 100%;
	padding-top: 50px;
	box-sizing: border-box;  
    	-moz-box-sizing: border-box;  
    	-webkit-box-sizing: border-box;  
}
#content_block {
	background-color: #ffffff;
	padding-top: 50px;
	box-sizing: border-box;  
    	-moz-box-sizing: border-box;  
    	-webkit-box-sizing: border-box;
	height: 100%;
	color: #000000;
}