Inline Styles for Email
Apply CSS inline to ensure consistent rendering across email clients.
Why Inline Styles?
Many email clients — most notoriously Gmail web before May 2016 and several mobile apps still today — strip or rewrite <style> blocks and external stylesheets. Inline style="..." attributes are the only CSS guaranteed to survive every client.
Author in External CSS, Ship Inlined
Writing inline styles by hand is unmaintainable. Author the email with normal <style> tags and class names, then run an inliner (Juice, Premailer, mjml) at build time to copy each rule into the matching element's style attribute before shipping.