how to force change in background color

Hey there,

I know how to change the color on regular code but even when I use the !important, the submit button is still yellow. Here is the code

#search-filter .user-search-button {
background-position: 0 -109px;
background-color: #ffffff !important;
border: medium none;
cursor: pointer;
height: 32px;
width: 81px;
}

What am I doing wrong?