Ah I see, it makes sense now that they aren't screenshots, and are instead interactive HTML/CSS/JS(?) bits.

Was suspicious of how high quality the screenshots were in mobile, but didn't bother to click on them. Neat!

No JS on the page, only HTML/CSS :)

The checkbox trick for the clickable Review button is so cool! Loved the easter egg links to various videos too

That's very impressive - how do you do this? I also see an IDE screen with the debugger in your other article about telegram - presumably also HTML/CSS

I just open Sublime Text (a basic text editor) and start typing away HTML/CSS until I've got something I like the look of. No fancy IDE features or anything, just typing out code into a file :).

I also use my browsers' DevTools for faster CSS iteration, and Paint.NET for concept art and comparing/measuring screenshots. Sometimes I even use Illustrator and/or Inkscape for some SVG stuff (which I manually edit in code afterwards) - in this blogpost I used Inkscape to recreate the cat emoji and the Chrome iframe error pixel art icon.