I've started a Free Software project that aims to be secure. The feedback I've received was mostly positive, but the negative feedback was very nondescript.

Source code:

https://github.com/paragonie/airship

Example website:

https://cspr.ng

I've been told, "This looks like something out of the 1990's," etc. but none of the UI criticism received was actionable by any stretch of the imagination.

What are some resources to learn better web design?