how to give border radius to one side code example

Example 1: css rounded corners at top only

border-radius: 10px     10px      0           0;
            // top-left top-right bottom-right bottom-left.

Example 2: how to round the corners of a div outline in css

div {
  outline: auto;
  outline-style: round;
}

Example 3: css border radius

-webkit-border-radius: 5px;
-moz-border-radius: 5px;
border-radius: 5px;