the largest plorblem preventing me choose vivaldi as all platforms browser, is that its mobile version , still don't support add browser extension, and they seem won't add this feature in future.
Recently people found that a lot of website genereated by ai has purple theme color[1], so when first glance on your site, I think it is a vibe code product immediatlly : )
On the website I built for my child, I added a dragable slider in the sidebar, allow user switch to different fonts. I made this for my own needs and am not sure if others would find it useful.
If someone is looking for a vertical/columnar math problem generator for kid, you can try this, which is I created for my 8-year-old son.
https://kids-math.xhtml.jp