Hi Simon
Thank you so much for this.
However I tried this and got no joy. So I decided to go digging.
First I found I do have this in the main Origami stylesheet
#menu .mobilenav-main-link .mobile-nav-icon {
width: 13px;
height: 20px;
background: green;
background: url(./images/navigate.png) no-repeat;
display: inline-block;
margin: 0 7px -3px 0;
}
Copying this into the custom css for my child theme and adding font-size; 0 as you suggested doesn't do anything
Next I found that the js that prebends the style is part of a js that constructs the mobile nav - this is working even though it's in the main Origami Theme folders not in my child theme so my best guess is that this is fine.
I then tried swapping out - in order - my custom css, random changes to the CSS. etc.
However in a last and final attempt I decided to take out the page-width change I made in the main style sheet and upload the original style sheet from Origami - put my page-width custom css in the custom css and - drum roll - it's back up and working.
Just to check I compared the style sheet I edited and the original and the ONLY thing that was different was the page width nothing else. So why this happened is a complete mystery to me. It might not even have anything to do with the original style sheet upload and just to do with reverting back to the original theme and re-applying the child - who knows.
Anyway it's been a useful learning experience!
Frank