I’ve been learning how to code a website recently… why is it so hard to center text??

Im currently new to self hosting, however I’ve started running my own website using NGINX (pronounced en-ginks of course) on a raspberry pi. It’s handling quite well, the most activity I’ve known of is my friend trying to DoS it by opening a bunch of tabs on it. Next steps: Keeping track of connections and DDoS protection (w/o cloudfare. Any suggestions?)