Customize order confirmation page

Hi, I'd like to change the “Order Confirmed” text and hide order info on the Order Confirmation page but the CSS I'm currently using based on info found in the forum doesn't work. I still see the default Order Confirmed text as well as the Order info text. 

I want to override both completely and replace the text with:

H1: Deposit Received
p: You will be notified via email when our campaign is live to receive early access to our exclusive discounts.

What I've done so far in CSS:

#confirmed-page {
  // Order Confirmed title
  div#confirmed-page h1 {
      visibility: hidden;
  }
  div#confirmed-page h1:before {
      visibility: visible;
      content: "Deposit Received";
  }  
  div#confirmed-page p {
    display: none;
}
  div#confirmed-page p:before {
      visibility: visible;
      content: "You will be notified via email when our campaign is live to receive early access to our exclusive discounts.";
  }  

Hi. Can you share link to order confirmation page? We can check easier