I know what fonts, colours and relative sizes I want things to be. This is only tangentially related, but a few years ago I set up my web browser to default to

I know what fonts, colours and relative sizes I want things to be. This is only tangentially related, but a few years ago I set up my web browser to default to white on black. Big mistake. I promptly found out that about half the websites out there specify a text color, but not a background color. Customization needs to be actively supported. It rarely comes for free.