<a href="javascript:let d=document,i=d.body.appendChild(d.createElement('input'));i.value='​';i.focus();i.select();d.execCommand('copy');i.parentNode.removeChild(i);void(0);">ZWS</a>

html {
	box-sizing: border-box;
}
*,*::before,*::after  {
	box-sizing: inherit;
	position: relative;
	background-repeat: no-repeat;
}
body {
	height: 100vh;
	display: grid;
	place-items: center;
}
a {
	display: block;
	background: #663399;
	color: #fff;
	padding: 1rem 2rem;
	border-radius: 0.5rem;
	&:not(:hover) {
		text-decoration: none;
	}
	
	&::before, &::after {
		display: block;
		text-align: center;
		width: 18rem;
		position: absolute;
		left: 50%;
		transform: translatex(-50%);

		color: #666;
	}
	&::before {
		content: "Zero-Width Space Bookmarklet";		
		top: -6rem;
		font-size: 180%;
	}
	&::after {
		content: "Click to add a zero-width space to your clipboard ...or drag the link to your bookmarks";
		bottom: -3rem;
		font-size: 80%;
	}
}