@mikeknight That was my favourite aspect also. Turns out you can do that with any theme, even the default.
Just add a CSS snippet like this, and change the colour to anything you want:
body {
--bold-color: #476af8;
--italic-color: #ff0000;
--link-color: #ffffcc;
--link-external-color: #ffffcc;
}
You can choose your colours on a site like this: https://colorpicker.me/, use the “Hex code” value.