Web Design Technologies

We have a requirement to Develop/Design a basic website that will have pages like home, aboutus, contact, , login/signup etc in the initial phase

Which methodology among the listed below ones, do you think as the best approach if the site is going to emerge into a full fledged web application with many higher functions in the later phases

1. CMS approach and use required plugins as and when required like wordpress
2. Traditional HTML/CSS along with any server side technologies like php, nodejs

Please provide the pros/cons of each approach if possible