Hey,
You could try choosing a broader selector from the list of options in Microthemer’s top toolbar. A broad selector might be a single class like “.entry-meta” (without quotes), rather than two classes e.g. “.post-123 .entry-meta.” When there are two classes, the first limits the scope of the second. So “.post-123 .entry-meta” target elements that have the class entry-meta, but only if they are inside an element that has the class “.post-123”. Using simply “.entry-meta”, you can target all elements that have the entry-meta class on all pages of the site.
I hope that helps. If you need more help, feel free to send me a link to the page you’re working on with a description of the element you want to target globally.
Thanks,
Sebastian