"What are your brand colors?" "A rainbow."

Been on your site. Very nice site. The CTA'S has bad contrast. If you upgrade the font weight will help.

The idea is great though!

Do you guys provide a dark mode?

I built a site for brand colours if that's what you need.
https://www.colorsandfonts.com

I am also working on brand style guidelines but is not live.

Https://www.colorsandfonts.com/brands.html

I almost missed the secret sauce! At first I thought you were just offering a book in another language. But what you are offering is a partially translated book. That is genius :-)

I suggest to make that more clear. Instead of

"In reading just one book, you can learn over 250 words & phrases in a foreign language."

maybe something more like:

"Using a curious and fun brain hack, our partially-translated books can help you learn over 250 words & phrases in a foreign language while actually enjoying yourself."

I've tried to learn another language so i feel the pain, and I think maybe the pain point you help solve is making it enjoyable, and with a focus on vocab which is the secret to enjoying a language as opposed to perfect grammar.

I think it looks great on a large screen but on mobile it looks too busy. I'd maybe decrease the opacity of the background patterns on mobile

I really like the design of this page. But I would suggest getting your call to action a bit more in front of your users. Above the fold your H1 and your button looks the same, also at the end of your site the CTA is not really in front of the user...

Also, the "view our books" or "go to bookshelf" is a really hard CTA, because you bring the user to a second site, where they believe they see books. So I would suggest to 2-3 "add email sign ups" on the page itself, and instead of "view books" you display some after the first fold...

And you should not use generic terms like: "view books" try using something like "start reading" or "learn a new language" which has a bit more emotion in it.