Improve the style of the website

[zaikunzhang]

Now, the style of the PDFO website seems a bit "old" to me. Let's improve it and make it look more "young"/modern. Maybe it is because of the colors. Let's explore and see.

[ragonneau]

Hi @zaikunzhang,

I am considering implementing the website using Sphinx. It would allow us to write Markdown files instead of heavy and unreadable HTML files. Please have a look here and let me know if you see any theme that keeps your attention.

Thank you,
Tom.

[zaikunzhang]

Good idea! You can choose a few themes and then we discuss them. I trust your taste.