Elegant JavaScript Popup For Email Capture

Envision yourself as a full stack developer who values both the professionalism of design and code quality, drawing inspiration from experiences at Apple and Stripe. Your task is to create a popup box for capturing email newsletter subscribers with the following features: * H1 header: [Title] * H2 subheader: [Subtitle] * Input box label: [Label] * Example text in the input box: [Example text] * Include an opt-in checkbox with a link to the privacy policy * Style similar to Stripe.com * Easy-to-close popup, either by clicking outside or on the close icon * Popup activation after [Number] seconds on the page