Why my website looks like "shit" and a bit more about TCP

So the current total size of my website is 7.46 KB, to be exact

Its served on github pages and it uses content-encoding zstd by default, transferring only 4.17KB with compression.

When you open up can.kurttekin.com on your browser the server has no idea about the amount of data can be transmitted per second (bandwith). 
Sending huge amount of data right off can cause packet loss, router owerwhelming etc.

So there is a method 
TCP Congestion Control is a set of strategies that TCP uses to prevent overloading the network.