Fifth Heading / Extra Heading / Another Heading

How do I add a 5th heading? I've spent 3 hours on this now! Trawling blogs etc. In 7.1FE. 

I have tried Markdown boxes but the formatting is horrible between desktop to phone.  And the bold/italic trick but I can't get that to work. 

I just need my new H5 to be a version of my H1 heading, but to be in a smaller REM; everything else is the same. And to be able to insert my new H5 into a paragraph sections as well as independent.

Thanks!

(Why can't there be a standard offering of extra P's and H's? It seems nuts.)

You can use Code Block

Something like this

<div class="heading-8">This is heading 8</div>
<div class="heading-7">Heading 7</div>
<style>
  /* size on desktop */
  .heading-8 {
  	font-size: 80px !important;
  }
   .heading-7 {
  	font-size: 70px !important;
  }
  /* size on mobile */
  @media screen and (max-width:767px) {
  	  .heading-8 {
  	font-size: 20px !important;
  }
     .heading-7 {
  	font-size: 30px !important;
  }
  }
</style>

Thanks Tuanphan. Will try soon.