How to set asp.net slider control css ? Control does not look properly when set css.

Question

Hi

when i set slider css , it is not rendered as expected.

The handle is not centered properly . Here is my css

.slider_handle
{
    border: medium ridge #00CC00;
    position: absolute;
    height: 8px;
    width: 7px;
    background-color: #008000;

}
.slider_rail
{
    border: medium solid #808080;
    position: relative;
    height: 6px;
    width: 420px;

    background-color: #F2C100;
    text-align: center;
    vertical-align: middle;
    top: 10px;
}

what i need to change ?