Improve file page CTAs to elicit conversions

Created by: rrhyne

File page CTAs currently utilize the alert component. This could reduce user trust in our alerts.

Additionally, file page CTAs could be improved to be related to additional functionality available to users. Some compelling functionality that may cause a user to sign up:

• When displaying a CSS (or SCSS)? file, highlight the CSS intel (yet to be published)l or css-stacking-contexts extension available to registered users.
• When a specific file type extension isn't available tout the ability to open in editor in a CTA

Tasks:

• Design a standard CTA (utilizing current homepage or search CTA designs) to present the message more appropriately.
• Create separate CTAs for specific content conditions