css rounded corners

/* The syntax of the first radius allows one to four values */
/* Radius is set for all 4 sides */
border-radius: 10px;

/* top-left-and-bottom-right | top-right-and-bottom-left */
border-radius: 10px 5%;

/* top-left | top-right-and-bottom-left | bottom-right */
border-radius: 2px 4px 2px;

/* top-left | top-right | bottom-right | bottom-left */
border-radius: 1px 0 3px 4px;

/* The syntax of the second radius allows one to four values */
/* (first radius values) / radius */
border-radius: 10px / 20px;

/* (first radius values) / top-left-and-bottom-right | top-right-and-bottom-left */
border-radius: 10px 5% / 20px 30px;

/* (first radius values) / top-left | top-right-and-bottom-left | bottom-right */
border-radius: 10px 5px 2em / 20px 25px 30%;

/* (first radius values) / top-left | top-right | bottom-right | bottom-left */
border-radius: 10px 5% / 20px 25em 30px 35em;

/* Global values */
border-radius: inherit;
border-radius: initial;
border-radius: unset;

#div1{
    width: 150px;
    height: 150px;
    background: #05ffb0;
    border-radius: 20px;
}