Business and Agency plans.
The compliance checkbox works on every plan. Making the popup look like it belongs to you requires Business or Agency.
Where
Go to Mollie Payments, then EU Consumer Compliance, and find Popup styling.
It only applies in popup mode, which is another reason to choose the popup.
What you can change
Border and corners. Border width, border colour, and the corner radius of the popup.
Button. Colour, text colour, hover colour, and corner radius.
Backdrop. The colour of the area behind the popup, and its intensity, which is how dark the page behind becomes.
Popup window. A subtle shadow, its colour, and an optional maximum width, given as something like 720px or 80%.
There is a live Preview on the same page, so you can see it as you go.
Why this is worth fifteen minutes
The consent popup appears at the single most delicate moment in your entire checkout: after your customer has decided to buy, and before they have paid.
A popup that looks like it belongs to your website is reassuring. A popup that looks like a stock browser dialogue, in a colour you have never used, looks like something went wrong. And a customer who thinks something went wrong stops.
Match your brand colours. Round the corners the way your site rounds them. Make the button the same colour as every other button they have clicked to get here.
Nobody will notice, and that is the point.