Custom CSS to make wikipedia look a little more readable based on css styles of medium.com. Sizes work for me on a macbook and windows with 1080p display. Used with MonoBook preset in appearance preferences.

wikipedia.custom.css

body {
	padding: 0 10%;
}
 
p {
	text-align: left;
	font-size: 18px;
	letter-spacing: 0.08px;
	line-height: 26px;
	word-wrap: break-word;
	margin-bottom: 30px;
}
 
h1 {
	font-size: 36px;
	font-family: jaf-bernino-sans, 'Lucida Grande', 'Lucida Sans Unicode', 'Lucida Sans', Geneva, Verdana, sans-serif;
}
 
h2 {
	font-size: 30px;
	font-family: jaf-bernino-sans, 'Lucida Grande', 'Lucida Sans Unicode', 'Lucida Sans', Geneva, Verdana, sans-serif;
}
 
h3 {
	font-size: 24px;
	font-family: jaf-bernino-sans, 'Lucida Grande', 'Lucida Sans Unicode', 'Lucida Sans', Geneva, Verdana, sans-serif;
}
 
div {
	font-family: jaf-bernino-sans, 'Lucida Grande', 'Lucida Sans Unicode', 'Lucida Sans', Geneva, Verdana, sans-serif;
	font-size: 14px;
	line-height: 24px;
}
 
.pBody li {
	margin: 10px 0 !important;
}
 
.pBody {
	padding-top: 5px !important;
	padding-bottom: 5px !important;
}
 
#firstHeading {
	margin: 50px 50px 0;
}
 
#bodyContent {
	margin: 0 50px;	
}
 
#content {
	font-family: freight-text-pro, Georgia, Cambria, 'Times New Roman', Times, serif;
	color: rgba(0, 0, 0, 0.8);
	border-right: 1px solid #999;
}
 
#p-personal li {
	margin-left: 10px !important;
}