norman

.content  {
	position: relative;
	overflow: hidden;
}
.content:after, .content:before {
		position: absolute;
		display: block;
		height: 100%;
		top: 0;
		left: 0;
		right: 0;
		transform: translateX(-100%);
		background: #ccc;
		content:  '';
}

<div class="wrapper">
  <header class="header">
    <div class="header__item">
    </div>
  </header>
  <main class="main">
  </main>
и так далее
</div>