September 15, 2014 Galen Mooney Video, Tutorial, HTML & CSS, Squarespace Customize Your Own Email Optin Form With CSS September 15, 2014 Galen Mooney Video, Tutorial, HTML & CSS, Squarespace I've had a lot of questions lately about how to customize the email optin form on your blog or website. Email marketing is a huge part of building your audience and it's important to have an optin that stands out on your website.