Search box – Changing colour – TwentyFourteen

Where can I go to change the colour of the search box on the left side-panel? I’ve tried modifying the styles.css file in the TwentyFourteen directory to no avail, changes are as below:

.search-toggle {
background-color: #ffffff;
/* background-color: #24890d;*/
cursor: pointer;
float: right;
height: 48px;
margin-right: 38px;
text-align: center;
width: 48px;
}

.search-box {
background-color: #ffffff;
/*background-color: #41a62a;*/
padding: 12px;
}