feat: improve the typography and looking of the entire website

[nazarepiedady]

I was reviewing the content of the website, namely its visual or visual presentation, and I found the line width, font-family, container alignment uncomfortable for a so dense content.

I have some UI and UX knowledge, and I do not recommend using or trusting on the font-family of the operating system because it could harm the reading experience of the content.

• I recommend centring the content for reading
• I recommend using the B612 font-family for the entire website
• I recommend setting a line width of at least 960px
• I recommend if possible adding a dark-mode feature

@mblayman, I could help, but only when I have time for that.