HTML {
	font-size: 16px;
}

BODY  {
	background: #000;
	height: 100vh;
	width: 100vw;
	font-family: Orbitron;
}

HEADER {
	position: relative;
}

	HEADER IMG {
		height: 100px;
	}

	HEADER::after {
		content: '';
		display: block;
		flex: 0 0 100%;
		transform: translatey( 1.5rem );
		height: 5px;
		background: linear-gradient( 90deg, rgb(255, 0, 0) 0%, rgb(255, 165, 0) 14.285%, rgb(255, 255, 0) 28.571%, rgb(0, 255, 0) 42.857%, rgb(0, 255, 255) 57.142%, rgb(0, 0, 255) 71.428%, rgb(75, 0, 130) 85.714%, rgb(255, 0, 0) 100%);
	}