Two Rounding Values for Different CSS Corners
If two values are specified, the first value specifies the rounding for the upper left and lower right corners, the second value specifies the rounding for the upper right and lower left corners:
<div id="elem"></div>
#elem {
width: 300px;
height: 100px;
border: 1px solid red;
border-radius: 10px 40px;
}
:
