which one is better?

[Unisoftdev]

To be honest, Python is always a good option but if you need just 3 static pages and no database then, either way, you will need a web server like Open LiteSpeed, Nginx, or Tornado which can handle the requests directly without Django or Flask, you don't need the frameworks. Flask is a better option, but you don't need anyone. Django provides just very basic development web server for development and both, Django and Flask need a web server for production. These frameworks are amazing for something bigger that needs a database and other connectivity, etc... But is there any need with 3 basic pages? I don't think so. If we really speak about static websites then you can use just HTML with CSS without any programming language but if you are gonna use Python then it doesn't mean that you need any CMS/framework. It doesn't give any sense if you don't go for the tools like admin interface, etc.

JavaScript, HTML5, and CSS3 work on the client side (while you don't use node.js).