This is the minor project which we were assigned to in the 3rd semester of my college where I was pursuing a degree in MCA (Masters in Computer Applications).
The project I was assigned to was to create the logo of the State Bank of India in CSS.
The markup / HTML was a no-brainer. It was only a couple lines of code.
However, the biggest challenge I faced was the styling / CSS. I had no idea how to create the logo in CSS, and to be fair, these types of things are usually done in sort of SVG editors. So naturally, I had to use websites like Google, Stack Overflow, GeeksforGeeks, CSS-Tricks, etc. After failing to find a solution over there, I asked on 'The Programmer's Hangout' as well as the 'Devcord' discord servers. it was on the latter that they pointed out a solution to me :- Pseudo-elements.
I had to spend 2 days learning it's intricacies; what it is and how it works.
And I'm so proud that I was finally able to make the logo using it.
This will remain special as it was the reason which motivated to finally start learning Version Control and Github.