margin wont work

no matter how much I put the margin bottom in pixels it wont go up

#search{
    display: block;
    height: 30px;
    width: 400px;
    border-bottom-left-radius: 100px;
    border-top-right-radius: 100px;
    padding-left: 20px;
    border-bottom-right-radius: 10px;
    font-family: Georgia, 'Times New Roman', Times, serif;
    font-size: large;
    position: fixed;
    margin-left: 600px;
    margin-bottom:100px;


}