Yeah the top left and right of the image are not as even as the bottom corners. The problem is padding squishing the image at the top, and altering it far more than intended. By removing padding-top in .imgCode, the radius will do it's thing.
Additionally, the card is a tad bit too small. Although that is not egregious in itself. Also watch out for the font-weight since the contrast between the paragraphs isn't strong enough. And make sure to include a default/backup typeface in the font-family in the top and bottom classes, should the main font fail.
Finally, make sure the to include padding in the first class, .box, so the box can "compress" on itself and grant space.
Otherwise, great attempt for your first time without help! I'm going through the same thing, so seeing your work was enlightening, since it offered an alternate path to how I approached it. And of course, seeing everything, all you did right and the flaws, increased my own understanding alot. Keep it up!