Implementing QR component using Flexbox

What are you most proud of, and what would you do differently next time?

• I always used TailwindCSS for a long time, but this time I completed the challenge from scratch with CSS!
• I will use SCSS next time

What challenges did you encounter, and how did you overcome them?

• I cannot center the div container vertically even though I understood and practiced Flexbox before
• To overcome the problem, I read my previous project

What specific areas of your project would you like help with?

• Are there any consequences if we do not create the same User interface as the design by the designer? Let's say it just looks like 90%.
• What are the common-used properties of Flexbox? I usually use display: flex, justify-content: * & align-items: * but I rarely use the others.
• Can you recommend some components or challenges that will help me enhance my Flexbox knowledge?

Thank you for spending time on my questions.