Need help to create a shadow border

Need help to create a shadow border (this is how it should look) This is my codepen.

Got it from here.

why don’t you use devtools to inspect the w3 code to see what values are they using for box-shadow ?
Alternatively, you may use some online box-shadow generator

I did that and i found a value box-shadow: 0px 2px 10px 0px rgba(0,0,0,12); and box-shadow: 0px 2px 5px 0px rgba(0,0,0,16); I tried for around 1hr 30min but couldnt get it to change color from black etc and some other things. I’ll try to use the generator thing and see if i can fix it.