Example | Notion

<!DOCTYPE>
<html>  
	<head>    
	<style>	
		h1 {	  
			background-color: red;	
		}	
		p {	  
			color: blue;	
		}	
	</style>  
	</head>  
	<body>	
		<h1>Heading</h1>	
		<p>This is Paragraph.</p>  
	</body>
</html>

https://codepen.io/linccodes/pen/mdqBpyK

The styles tag's selectors p and h1 point to the HTML elements you want to style: <p> and <h1>. Blue is the value of color, which is a property.