You can customize the colours and logo of your unsubscribe page.
To do that, go to the upper right corner of the page and click on your name.
From the dropdown menu click on "Preferences".
Then click on "Unsubscribe pages" (1) and then click on "Add" (2).
On the right side a form appears, where you can customize your unsubscribe page. You can change the color of the unsubscribe button ("Primary color"), the background color ("Secondary color"), add your company's logo and also add custom CSS styles. The name field is the name of your unsubscribe template in Smaily that only you can see, this will not be displayed in the unsubscribe form.
After you have done the changes, click on "Add".
If you want to see how your unsubscribe form looks like, you have to send yourself a campaign to test it.
Start creating a campaign as you usually do (here's a manual how to send a campaign). On the last (4th) step of creating the campaign, you have the option to choose the unsubcribe theme. Choose from the dropdown menu the unsubscribe form you created and send the test campaign. Then click on the "Unsubscribe" link in your email and you can see how the custom unsubscribe page looks.
This is also how you choose the unsubscribe form when sending out campaigns.