Remove header from confirmation page

Site URL: https://etiennemellor.com

How do you remove the header from the confirmation page in Squarespace? 

Also, how can you bring the text (order #, your order of $.... and If you dont..." ) closer together, not skipping lines?

Here is a link to the page

https://etiennemellor.com/checkout/order-confirmed?oid=5ff60e00038bd1505d061e61&authCode=NWZmNjBlMDAwMzhiZDE1MDVkMDYxZTYxOjIwMjEtMDEtMDZUMTk6MjI6MzkuODY2WkuI_uSXm9XF2WbjxKo4Z0-ClMGWb9h4B1PkMXy2PdL2

Thank you,

I'm also wondering how to remove the header and footer on the order confirmatiom page. 😓

Add to Design > Custom CSS

/* remove header footer order page */
div#confirmed-page {
	header#header, footer.sections {display: none;}
}