"A cool-looking box" assessment

Hey!
I was working on ‘A cool looking box’ section. I wonder, if everything’s fine with my css-code? Have a look, please:

html {
font-family: sans-serif;
}

/* Your CSS below here */

/* computed size=16px(default)=1rem => font-size=18px(we need)/16px=1.125rem */

p {
width: 200px;
height: 50px;
font-size: 1.125rem;
line-height: 2.8;
text-align: center;
background: linear-gradient(to left top, rgba(0, 0, 0, 0.5) , rgba(0, 0, 0, 0.2) 30%, rgba(0, 0, 0, 0));
background-color: red;
color: red;
text-shadow: 2px 2px 2px black,
-2px -2px 2px black;
border: 1px solid rgb(201, 19, 19);
border-radius: 0.5rem;
box-shadow: 4px 4px 3px rgb(59, 59, 59),
inset 3px 3px 3px rgba(255, 255, 255, 0.75),
inset -3px -3px 3px rgba(0, 0, 0, 0.5);
}