To change font weights for all headings at once in Webstudio, you need to work with the style tokens in the global root. While you can set font family and color globally, font weight typically needs to be set individually for each heading level (H1, H2, H3, etc.). However, you can create a shared token for font weight and apply it to multiple heading elements. Click on the font weight property in the style panel to access the token system. You can create a font weight token and then apply that same token to all your heading elements for consistency. This approach allows you to change the weight globally by updating the token value.