<div></div>
html, body { display: grid }

html { height: 100% }

div {
	--l: bottom, 
		#fff 20%, #eee 0 40%, 
		#ddd 0 60%, #ccc 0 80%, #bbb 0;
	background: 
		/* pattern layer */
		linear-gradient(90deg, #fff, #808080, #fff) 
			50%/ 2.5%, 
		/* map layers */
		linear-gradient(to left var(--l)), 
		linear-gradient(to right var(--l));
	background-blend-mode: multiply;
	filter: contrast(27)
}
View Compiled

External CSS

  1. https://codepen.io/thebabydino/pen/evPbxv.css

External JavaScript

  1. https://codepen.io/thebabydino/pen/evPbxv.js