Responsive QR code component, html & css

Great job on completing the challenge. Few things I want to point out:

• The background color of body is different compared to the design. (Color codes are provided in style-guide.md file).
• Giving some shadow to the card.
• Padding inside the card is more compared to the design.
• Instead of the generic div tag, try using semantic html tags.
• Avoid giving a fixed height and width. You should use max-width and calc for such operations.
• Should use relative units instead of px for size.