[Bug]: Markdown bold is too subtle after the redesign, even with New design disabled #25395

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Steps to reproduce

1. Type Regular text and **bold text** in the rich text composer.
2. Send the message.
3. Compare the bold formatting in the composer and the sent message.
4. Disable Settings → Beta → New design and repeat.

Expected behavior

Bold text remains clearly distinguishable from regular text, with consistent emphasis between the composer and rendered messages.

Actual behavior

Bold is noticeably lighter after sending: in the message, the weight is 600, while in the composer, it's 700.

In the new default font Inter, I can see the difference between bold and not bold, but it's inconsistent with the composer:

I don't like Inter, so I'd like to choose a different font. In some other fonts, I can barely see the new 600 bold; in others, I can see it, but it doesn't jump out at me. So Inter is basically required now, if I want to clearly see bold. Examples:

Disabling New design does not restore the previous appearance.

Cause

The redesign (#24865) introduced this global rule:

.chat-markdown strong {
  font-weight: 600;
}

This changes message bold to semibold, while the composer uses 700 (bold). The rule is not scoped to the New design toggle.

Impact

Cosmetic issue

Version or commit

0.1.3-nightly.20261026.3710

Environment

Windows desktop

Logs or stack traces

Screenshots, recordings, or supporting files

Here's one of the clearer alternative fonts, Literata, where I can still barely see the switch to bold:

Here's one of the worst fonts, Merriweather, where it's basically invisible:

Workarounds

I've found Noto Sans to be a good workaround:

Proposed Fix

Please restore to normal 700 bold so that we can use other fonts.

Or commit to 600 bold in composer too, but make this weight configurable in the theme.