QR code page

Replace <div id="container"> with the main tag to fix the accessibility issue. click here for more on web-accessibility and semantic html

There is no need for a height, width ,max-width, min-width in the body.

To center #container on the page page, add min-height:100vh; display: flex; align-items: center: justify-content: center; or min-height:100vh; display: grid place-items: center to the body.

To center  #container on the page using flexbox:
body{
min-height: 100vh;
display: flex;
align-items: center;
justify-content: center;
}

To center #container on the page using grid:
body{
min-height: 100vh;
display: grid;
place-items: center;
}

Use relative units like rem or em as unit for the padding, margin, width values and preferably rem for the font-size values, instead of using px which is an absolute unit. For more on CSS units Click here

Add a padding value for all the sides eg. padding:15px. give the img a max-width of 100% instead a width and a height value. Give h1 and p a font-size of 15px.

Hope am helpful.

Well done for completing this challenge. HAPPY CODING