Revisit figcaption styles

[kfranqueiro]

Figcaptions are currently displayed in bold text, due to styles defined WAI-website-wide in /WAI/assets/css/style.css.

This can perhaps be overwhelming for captions that run particularly long, and also limits options to emphasize content within those captions, as pointed out in #4055 (comment).

On the other hand, the existing bold styles do make it easy to distinguish figcaptions from ordinary paragraphs of text within the body.

Some thoughts that came up in discussion on the backlog TF call on 2025-02-21:

• Make only the leading "Figure N" part of the caption bold
  • Currently these are added by the build system to Understanding docs as separate paragraphs before the content, but not Techniques
  • One technique (G211) has them written in-line within the content
  • If we want to consistently settle on the former, we should remove the few inline instances and consistently apply this across Techniques and Understanding
• Consider options to ensure long figcaptions are still distinguishable from subsequent content:
  • Increase contrast of the divider line below the figure
  • Add styles to figure + figcaption to make the caption match the width of the image? (This may be possible with CSS inline-grid + figcaption width trickery)
    • We would probably want to set a min-width, since some figures are not very wide (e.g. Figure 4 in Non-text Contrast)

WIP exploring options on my fork

Example before and (proposed) after: