"Click here to confirm" link in confirmation email renders as white in Outlook

[buttondown-engineering]

The confirmation email template appears to apply a global CSS rule that forces all links to #ffffff, causing the primary confirmation link ("Click here to confirm") to render white on a white background in Outlook.

Steps to reproduce

1. Subscribe to a Buttondown newsletter.
2. Open the confirmation email in Outlook (reproduced in Outlook).
3. Observe that the "Click here to confirm" link is white/invisible.

Root cause

The generated HTML contains:

a {
    color: #ffffff !important;
    text-decoration: underline;
}

The confirmation link is emitted as:

<a href="...">Click here to confirm</a>

with no inline color override, so it inherits the global white color.

By contrast, the newsletter title link is rendered as:

<a href="..." style="color: inherit !important;">

which overrides the global rule and displays correctly.

Expected behaviour

The confirmation link should render in a visible link colour (or inherit the surrounding text colour) across supported email clients.

Actual behaviour

The primary CTA link is rendered white in Outlook, making it effectively invisible against the white background.

Notes

• Reproduced with multiple generated confirmation emails.
• Gmail and Outlook versions of the MIME source are effectively identical, including the global a { color: #ffffff !important; } rule, so this does not appear to be transport-related.
• This looks like a template/CSS issue rather than an Outlook-specific rendering bug.
• The global selector may have been intended for button links only (e.g. .buttondown-button) but is currently applied to every <a> element.

[linear-code]

BUG-402