In your Child Theme or CSS Editor Plugin try this code:
.logo_tagline {
font: 400 14px/1.2em Cinzel;
}
Just edit the 14px.
*Note
If your theme has a custom CSS Editor in it, you can also paste the code in there.
Never edit core CSS or PHP files under Appearance > Editor. Your edits will be deleted when the theme is updated.
Thanks for trying, sorry complete novice, as far as I can see I can get no access to styles or theme set up. I have a general options menu which has lots of different header descriptions with their various font , size colour etc, but I have changed everyone of them to try and change the tagline and it doesn’t work. thought there may be another way that was easy!!!???