Fix website local font paths and font-weight CSS (#12966)
* fix font weight
* fix font path for website
* add changeset
* add changeset
* update stale theme.css
---------
Co-authored-by: gradio-pr-bot <gradio-pr-bot@users.noreply.github.com>
Co-authored-by: Freddy Boulton <41651716+freddyaboulton@users.noreply.github.com>
