@jaseg @cato Not just ancient devices, but unless it's changed since I last looked, a lot of modern E-mail clients/groupware programs just render HTML E-mail badly for some reason.
Also, all the advantages of things like flexbox and grid really don't apply to QR codes.
Still, could've been an image...
The main problem with email clients is that they ignore <style> elements. You can apply inline CSS with style="…", but that's it.
Some email clients don't ignore <style> elements, mind you, but webmail in particular usually does. You don't want the email's styles to apply to the entire webmail user interface, after all.
These days, shadow DOM can be used to confine the effects of <style> to just the email, but Gmail doesn't do that for some reason.
Was it really necessary for you to remind me that Outlook exists? 😖