Como posso visualizar CSS modificado rapidamente usando ferramentas de desenvolvedor?
Firefox
Edits that you make in the Rules view are reflected in the Style Editor, and vice versa.
Fonte Ferramentas para desenvolvedores do Firefox Examine e edite as CSS
To open the Style Editor choose the "Style Editor" option from the "Web Developer" menu (which is a submenu in the "Tools" menu on the Mac). The Toolbox will appear at the bottom of the browser window, with the Style Editor activated:
Fonte Editor de estilo das ferramentas de desenvolvimento do Firefox
Chrome
Persisting Changes
Upon an external style sheet rule modification, the respective resource text is updated in the Resources panel, and the revision history is stored for such style sheet resources until the DevTools window is closed.
Activate the Resources panel, find tutorial.css in the resource tree. Note that the tree node is expandable. Click the arrow next to the node title, and you will see all the resource modifications that you have made above.
Select any revision to see its differences from the original stylesheet resource, highlighted line-wise.
You can drag and drop a stylesheet revision node into most text editors to export the revision content.
Fonte Como editar estilos