My QR Code Design. I used html and Css

Hi @Richiemore 👋, good job completing this challenge, and welcome to the Frontend Mentor Community! 🎉

• There are two modern CSS techniques to center elements:

Using flexbox layout:

body {
   margin: 0;
   min-height: 100vh;
   display: flex;
   flex-direction: column;
   justify-content: center;
   align-items: center;
}

Using grid layout:

body {
   margin: 0;
   min-height: 100vh;
   display: grid;
   place-content: center;
}

Links with more information:

• The Complete Guide to Centering in CSS.
• A Complete Guide to Flexbox (CSS-Tricks).
• How TO - Center Elements Vertically (W3Schools).
• CSS Layout - Horizontal & Vertical Align (W3Schools).

Good job, and happy coding! 😁