CSS for Highlighting Text

Hello,

I would be very grateful if you could help me. 

I'm trying to replicate the highlight effect exactly as per this image (on the title "Step 1". 

Could anyone help me please? 

you could do it in a code block. add a code block and use the following HTML / Style

<div style="background-color:#CB4342; color:white; font-weight:bold; padding:0.5rem 1.5rem; border-radius:4px; display:inline-block; font-size:large;">
  STEP 1
</div>

if you're going to use this in more than one place, then add the style bit as a class to the Custom CSS in your site (go to Design from the main menu of the editor) like this

.redLabel {
	background-color:#CB4342; 
	color:white; 
	font-weight:bold; 
	padding:0.5rem 1.5rem; 
	border-radius:4px; 
	display:inline-block; 
	font-size:large;
}

and then in your code blocks use this class like this

<div class="redLabel">Step 1</div>

Fantastic! Thank you so much.