Background colour on social links in emails not working

[KimberleyCook]

Description of the issue 📄

The background colour for the codebar social links in emails is not working.

Screenshots 📷

Steps to fix 🛠

To do 📋

• Claim this issue (comment below, or assign yourself if you are part of the codebar org)
• Fork and clone the repository
• Update the relevant files. Follow the steps to fix section in this issue.
• Commit your changes as one commit. Use the title of this issue as your commit message
• Submit a pull request
• Mention this issue in the PR description by including it's number
• Have your pull request reviewed & merged by a codebar team member

[Agboolafeyikemi]

Hi @KimberleyCook, I'd like to claim this one, I dug into why January's fix (#2437) didn't take effect and found the root cause.

Production emails get their CSS inlined from /assets/email.css the URL that was hard-coded in the mailer header until #2715. That URL currently serves a copy of the stylesheet from before November 2024 (I verified it byte-for-byte against git history), with Cache-Control: public, max-age=31556952, i.e. cached for a year. That old file only has background rules for a.fb and a.tw , so with today's markup only the Facebook button gets a colour, and Slack/LinkedIn/Bluesky/YouTube render as white text on no background. Editing email.css can never fix this while the stale copy keeps being served, which is why the previous fix didn't help.

#2715's digest-stamped URL should prevent this recurring, but belt-and-braces I've opened a PR that inlines the background colour on each social link directly in the partial email clients only reliably render inline styles anyway, so the buttons no longer depend on which version of email.css premailer resolves.

Ops note: it's probably worth purging the CloudFlare cache for /assets/email.css and restarting the dynos, since premailer-rails also caches CSS per-URL in-process in production.