I found it really difficult to align the bottom text (created by..) with the avatar image. In the end, I had to hard code it in. How could I center the text to the center of the image?
You asked how you could align the text to the center of the image. An easy way to do this is use Flexbox. I saw you used it in your body to center the card on the page.
You can wrap your image and your text in a div, you then display: flex on this div and then can use align-items: center to do what you are looking for. Then you can apply a gap to this same div for the spacing between the image and the text, or use a margin on either one if you like it better.
You said you have a problem on button hover adding 2px to the card which is normal.
An easy way to fix this is to add the same border to your regular button styling rules instead of having it only on the hover.
This way the border is always there but on hover when the background change you can now see the border without changing the dimension of the button.
You should consider adding other breakpoints for better responsiveness.
And maybe increase your media query max-width to something bigger than 375 pixel.
You can see for yourself in your browser Devtools , between 375px and 1300px screen width, the left part containing all the information becomes very narrow and tall.
This looks very good i have just finished this challenge myself.
You are not using the right font (you are using Red Hat Display, instead of Outfit).
You should maybe add an alt to your img.
Consider editing the README.md using the README-template.md to give us more information of how you approched this challenge and what you learned.