Styling a formspree contact form

I’m using Ghost Pro with the Lyra theme - and I’m trying to set up a contact page.

I’ve followed the instructions here:

But I’m not clear about where to insert the styling code, so I’ve left that out. The contact page I’ve created works, but it looks terrible! check it out here:

Can anyone tell me where I need to insert the styling code, so that the form looks a bit more presentable… Like the example shown on the tutorial page?



Update: I’ve managed to solve this, after a fashion! I discovered that what I needed to do was to enclose the CSS code I’d copied from the tutorial page within the terms and and then insert this block of code into the header of the page. I ended up with a white form on a white background, so I attempted to change the page background color, by adding the following:

body {
background-color: lightblue;

Unexpectedly, this had the effect of putting a blue border around the form’s text boxes, which looks fine, to me: