[desktop] Markdown tables ignore UI font size and remain at 14px

What version of the Codex App are you using?

26.818.41509 (build 6962)

What platform is your computer?

macOS 15.6.1

What issue are you seeing?

Markdown tables in Codex Desktop do not follow the configured UI font size. With the UI font size set to 13 px, surrounding chat text renders at 13 px, but Markdown table text remains at 14 px and is visibly larger—especially with CJK content and narrow columns.

The current bundled stylesheet applies a hardcoded rule equivalent to:

.MarkdownRoot .Table {
  font-size: 14px;
}

This means lowering the UI font size makes tables look disproportionately large.

What steps can reproduce the bug?

1. Open Settings → Appearance.
2. Set the UI font size to 13 px.
3. Render an assistant response containing a Markdown table.
4. Compare the table text with the paragraph immediately before or after it.

What is the expected behavior?

Markdown tables should inherit the configured UI/chat font size. Alternatively, Appearance settings could expose a separate Markdown table font-size control.

Additional information

• sansFontSize = 13
• codeFontSize = 13
• The behavior is independent of the selected monospace font.
• Table headers use a heavier weight and cells have generous vertical padding, which makes the mismatch more noticeable.