Responsive QR Code Component usiing Flexbox

Some recommendations regarding your code that could be of interest to you.

• In order to center the card, you can add flexbox and min-height: 100vh to the body

body {
  background-color: hsl(212, 45%, 89%); 
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}

• After adding them, you don't need the .content, so you can remove it

/* 
.content {
    display: flex;
    flex-flow: column;
    justify-content: center;
    align-items: center;
    max-width: 90%;
    margin: 100px auto;
    background-color: hsl(212, 45%, 89%);
    padding: 1.3rem 0 1.3rem 0;
    border-radius: 5px;
} 
*/

Hope I am helpful. :)