@ed: “What do you think of the yellow then?”
I saw it a few minutes ago, and it looked OK but the post titles had mysteriously lost their bold attribute.
Now I look again and the bold is back, but the text has turned grey (rgb(85, 85, 85) instead of true black.
“That’s a level of control I don’t have. All I can pick is a colour scheme.”
If I understand https://op111.net/posts/2008/08/wordpress-child-themes/ correctly, it should only require a style.css with an @import statement and a line or two of css for any element you want to change.
But probably best to just go with the yellow (or whatever other colour is agreed) to get the new site launched, and then think about more detailed tweaks when the dust has settled.