What is the css code for rounded border or corner?

Question

CSS

Answer 1

it's border-radius
check here for reference
https://www.w3schools.com/css/css3_borders.asp

Answer 2

p {
border-style:solid;
border-radius:15%;
width:50px;;
height:50px;
padding:5px;
}

notice that i gave 15% you can reduce or increase the amount.

increasing amount will increase the curve of shape
in this case it is square and increasing amount 15% to 100% will change shape to circle if your shape is rectangle and radius is 100% than you will have ellipse shape.

and do not forget to use padding when you are using radius 100% your text which are close to corners will not shown

here is an example for you
https://code.sololearn.com/Wh5CWojlL43b/?ref=app