HTML & CSS QR Code

Congratulations well done. Just a few tips

• Make a habit of using css reset.

/* this is a simple css reset. this reset will remove unnecessary empty spaces */
* {
    margin: 0;
    padding: 0;
    box-size: border-box;
}

• In this case you can use flexbox or css grid to place the card in the middle of the page

body { 
    display: flex; 
    justify-content: center;
    align-items: center;
    flex-direction: column;
    min-height: 100vh; /* make a habit of setting the height of the body to min-height 100vh. this will make the height more responsive */
    
    font-size: .8rem;
    font-family: "Outfit", sans-serif;
    text-align: center; 
    color: hsl(218, 44%, 22%);
    background-color: hsl(212, 45%, 89%);	
}

main {
    width: 350px;
    height: 500px;
    background-color: white;
/*     margin: 10% auto; */ /* you can remove this, flexbox will do the job */
    padding: 3% 1% 0 1%;
    border-radius: 10%;
}

• If the border radius is less than 50%, avoid using % to dimension border radius. Use px, rem, em instead. You have a border radius of 10% if you look closer you will see a difference in the radius.